diff --git a/example/src/root.zig b/example/src/root.zig
index bc0384d..3f3551d 100644
--- a/example/src/root.zig
+++ b/example/src/root.zig
@@ -307,7 +307,7 @@ pub fn run(allocator: std.mem.Allocator, io_optional: ?std.Io) !void {
     // PlainDate: add, subtract, with, equals, since, until, withCalendar
     const date_added = try date.add(dur);
     const date_sub = try date.subtract(dur);
-    // const date_with = try date.with(.{ .year = 2025 });
+    const date_with = try date.with(.{ .year = 2025 });
     const date_eq = date.equals(date);
     const date_since = try date.since(date, Temporal.PlainDate.DifferenceSettings{});
     const date_until = try date.until(date, Temporal.PlainDate.DifferenceSettings{});
@@ -320,7 +320,7 @@ pub fn run(allocator: std.mem.Allocator, io_optional: ?std.Io) !void {
         \\ - since self: {s}
         \\ - until self: {s}
         \\ - withCalendar: {s}
-        \\ - with year=2025: {{s}}
+        \\ - with year=2025: {s}
         \\
         \\
     ,
@@ -331,7 +331,7 @@ pub fn run(allocator: std.mem.Allocator, io_optional: ?std.Io) !void {
             try date_since.toString(allocator, .{}),
             try date_until.toString(allocator, .{}),
             try date_with_cal.toString(allocator, .{}),
-            // try date_with.toString(allocator, .{}),
+            try date_with.toString(allocator, .{}),
         },
     );
 
@@ -399,7 +399,7 @@ pub fn run(allocator: std.mem.Allocator, io_optional: ?std.Io) !void {
         try tm_until.toString(allocator, .{}),
     });
 
-    // PlainYearMonth: add, subtract, with, equals, since, until, withCalendar
+    // PlainYearMonth: add, subtract, with, equals, since, until
     const dur_ym = try Temporal.Duration.from("P1M");
     defer dur_ym.deinit();
     const ym_added = try ym.add(dur_ym);
@@ -427,11 +427,10 @@ pub fn run(allocator: std.mem.Allocator, io_optional: ?std.Io) !void {
         try ym_until.toString(allocator, .{}),
     });
 
-    // ZonedDateTime: add, subtract, round, with, equals, since, until, withCalendar, withPlainTime, withTimeZone
+    // ZonedDateTime: add, subtract, round, equals, since, until, withCalendar, withPlainTime, withTimeZone
     const zdt_added = try zdt.add(dur);
     const zdt_sub = try zdt.subtract(dur);
     const zdt_rounded = try zdt.round(.{ .smallest_unit = Temporal.ZonedDateTime.Unit.hour });
-    // const zdt_with = try zdt.with(allocator, .{ .year = 2025 });
     const zdt_eq = zdt.equals(zdt);
     const zdt_since = try zdt.since(zdt, Temporal.ZonedDateTime.DifferenceSettings{});
     const zdt_until = try zdt.until(zdt, Temporal.ZonedDateTime.DifferenceSettings{});
@@ -443,7 +442,6 @@ pub fn run(allocator: std.mem.Allocator, io_optional: ?std.Io) !void {
         \\ - add duration: {s}
         \\ - subtract duration: {s}
         \\ - round to hour: {s}
-        \\ - with year=2025: {{s}}
         \\ - equals self: {}
         \\ - since self: {s}
         \\ - until self: {s}
@@ -456,7 +454,6 @@ pub fn run(allocator: std.mem.Allocator, io_optional: ?std.Io) !void {
         try zdt_added.toString(allocator, .{}),
         try zdt_sub.toString(allocator, .{}),
         try zdt_rounded.toString(allocator, .{}),
-        // try zdt_with.toString(allocator, .{}),
         zdt_eq,
         try zdt_since.toString(allocator, .{}),
         try zdt_until.toString(allocator, .{}),
@@ -464,6 +461,351 @@ pub fn run(allocator: std.mem.Allocator, io_optional: ?std.Io) !void {
         try zdt_with_time.toString(allocator, .{}),
         try zdt_with_tz.toString(allocator, .{}),
     });
+
+    // ----
+    // API coverage examples for the remaining public methods
+    // ----
+
+    const dur_init = try Temporal.Duration.init(0, 1, 0, 2, 3, 4, 5, 6, 7, 8);
+    const dur_from_partial = try Temporal.Duration.from(Temporal.Duration.PartialDuration{ .minutes = 90 });
+    const dur_compare = try dur.compare(dur2, .{});
+    const dur_locale_supported = dur.toLocaleString(allocator) != error.TemporalNotImplemented;
+    std.log.info(
+        \\Duration Coverage
+        \\ - init: {s}
+        \\ - from partial: {s}
+        \\ - compare(dur, dur2): {}
+        \\ - sign: {s}
+        \\ - blank: {}
+        \\ - microseconds: {d}
+        \\ - toJSON(): {s}
+        \\ - toLocaleString implemented: {}
+        \\
+        \\
+    , .{
+        try dur_init.toString(allocator, .{}),
+        try dur_from_partial.toString(allocator, .{}),
+        dur_compare,
+        @tagName(dur.sign()),
+        dur.blank(),
+        dur.microseconds(),
+        try dur.toJSON(allocator),
+        dur_locale_supported,
+    });
+
+    const instant_from_ms = try Temporal.Instant.fromEpochMilliseconds(1_704_067_200_000);
+    const instant_from_ns = try Temporal.Instant.fromEpochNanoseconds(1_704_067_200_000_000_000);
+    const instant_from_str = try Temporal.Instant.from("2024-01-01T00:00:00Z");
+    const instant_until = try inst1.until(inst2, Temporal.Instant.DifferenceSettings{});
+    const instant_zdt = try inst1.toZonedDateTimeISO(try Temporal.Instant.TimeZone.init("UTC"));
+    defer instant_zdt.deinit();
+    std.log.info(
+        \\Instant Coverage
+        \\ - fromEpochMilliseconds: {s}
+        \\ - fromEpochNanoseconds: {s}
+        \\ - from string: {s}
+        \\ - equals(from ms, from ns): {}
+        \\ - until inst2: {s}
+        \\ - toJSON(): {s}
+        \\ - toLocaleString(): {s}
+        \\ - toZonedDateTimeISO(): {s}
+        \\
+        \\
+    , .{
+        try instant_from_ms.toString(allocator, .{}),
+        try instant_from_ns.toString(allocator, .{}),
+        try instant_from_str.toString(allocator, .{}),
+        Temporal.Instant.equals(instant_from_ms, instant_from_ns),
+        try instant_until.toString(allocator, .{}),
+        try inst1.toJSON(allocator),
+        try inst1.toLocaleString(allocator),
+        try instant_zdt.toString(allocator, .{}),
+    });
+
+    const now_zdt_supported = Temporal.Now.zonedDateTimeISO() != error.TemporalNotImplemented;
+    std.log.info(
+        \\Now Coverage
+        \\ - timeZoneId(): {s}
+        \\ - zonedDateTimeISO implemented: {}
+        \\
+        \\
+    , .{
+        Temporal.Now.timeZoneId(),
+        now_zdt_supported,
+    });
+
+    const date_cal = try Temporal.PlainDate.calInit(2024, 2, 2, "iso8601");
+    const date_from = try Temporal.PlainDate.from("2024-02-02");
+    const date_md = try date.toPlainMonthDay();
+    const date_ym = try date.toPlainYearMonth();
+    const date_zdt = try date.toZonedDateTime(.{ .time_zone = "UTC", .plain_time = tm });
+    const date_locale_supported = date.toLocaleString(allocator) != error.TemporalNotImplemented;
+    const date_valueof_supported = date.valueOf() != error.TemporalValueOfNotSupported;
+    const date_with_coverage = try date.with(.{ .year = 2025, .month = 3, .day = 4 });
+    std.log.info(
+        \\PlainDate Coverage
+        \\ - calInit: {s}
+        \\ - from string: {s}
+        \\ - compare(date, from): {}
+        \\ - calendarId: {s}
+        \\ - dayOfWeek/dayOfYear: {}/{}
+        \\ - daysInWeek/daysInMonth/daysInYear: {}/{}/{}
+        \\ - monthCode/monthsInYear: {s}/{}
+        \\ - inLeapYear: {}
+        \\ - era/eraYear: {any}/{?}
+        \\ - weekOfYear/yearOfWeek: {?}/{?}
+        \\ - toPlainMonthDay: {s}
+        \\ - toPlainYearMonth: {s}
+        \\ - toZonedDateTime: {s}
+        \\ - toJSON(): {s}
+        \\ - toLocaleString implemented: {}
+        \\ - valueOf supported: {}
+        \\ - with year/month/day: {s}
+        \\
+        \\
+    , .{
+        try date_cal.toString(allocator, .{}),
+        try date_from.toString(allocator, .{}),
+        Temporal.PlainDate.compare(date, date_from),
+        try date.calendarId(allocator),
+        date.dayOfWeek(),
+        date.dayOfYear(),
+        date.daysInWeek(),
+        date.daysInMonth(),
+        date.daysInYear(),
+        try date.monthCode(allocator),
+        date.monthsInYear(),
+        date.inLeapYear(),
+        try date.era(allocator),
+        date.eraYear(),
+        date.weekOfYear(),
+        date.yearOfWeek(),
+        try date_md.toString(allocator),
+        try date_ym.toString(allocator),
+        try date_zdt.toString(allocator, .{}),
+        try date.toJSON(allocator),
+        date_locale_supported,
+        date_valueof_supported,
+        try date_with_coverage.toString(allocator, .{}),
+    });
+
+    const dt_cal = try Temporal.PlainDateTime.calInit(2024, 2, 2, 13, 45, 30, 123, 456, 789, "iso8601");
+    const dt_from = try Temporal.PlainDateTime.from("2024-02-02T13:45:30.123456789", .{});
+    const dt_plain_time = try dt.toPlainTime();
+    const dt_zdt = try dt.toZonedDateTime(.{ .timeZone = "UTC" });
+    const dt_valueof_supported = dt.valueOf() != error.ComparisonNotSupported;
+    std.log.info(
+        \\PlainDateTime Coverage
+        \\ - calInit: {s}
+        \\ - from string: {s}
+        \\ - compare(dt, from): {}
+        \\ - calendarId: {s}
+        \\ - dayOfWeek/dayOfYear: {}/{}
+        \\ - daysInWeek/daysInMonth/daysInYear: {}/{}/{}
+        \\ - monthCode/monthsInYear: {s}/{}
+        \\ - inLeapYear: {}
+        \\ - era/eraYear: {any}/{?}
+        \\ - weekOfYear/yearOfWeek: {?}/{?}
+        \\ - millisecond/microsecond/nanosecond: {}/{}/{}
+        \\ - toPlainTime: {s}
+        \\ - toZonedDateTime: {s}
+        \\ - toJSON(): {s}
+        \\ - toLocaleString(): {s}
+        \\ - valueOf supported: {}
+        \\
+        \\
+    , .{
+        try dt_cal.toString(allocator, .{}),
+        try dt_from.toString(allocator, .{}),
+        Temporal.PlainDateTime.compare(dt, dt_from),
+        try dt.calendarId(allocator),
+        dt.dayOfWeek(),
+        dt.dayOfYear(),
+        dt.daysInWeek(),
+        dt.daysInMonth(),
+        dt.daysInYear(),
+        try dt.monthCode(allocator),
+        dt.monthsInYear(),
+        dt.inLeapYear(),
+        try dt.era(allocator),
+        try dt.eraYear(),
+        try dt.weekOfYear(),
+        try dt.yearOfWeek(),
+        dt.millisecond(),
+        dt.microsecond(),
+        dt.nanosecond(),
+        try dt_plain_time.toString(allocator),
+        try dt_zdt.toString(allocator, .{}),
+        try dt.toJSON(allocator),
+        dt.toLocaleString(allocator),
+        dt_valueof_supported,
+    });
+
+    const md_from = try Temporal.PlainMonthDay.from("02-02");
+    const md_with = try md.with(.{ .day = 3 });
+    const md_date = try md.toPlainDate(2024);
+    const md_valueof_supported = md.valueOf() != error.ValueError;
+    std.log.info(
+        \\PlainMonthDay Coverage
+        \\ - from string: {s}
+        \\ - equals(from): {}
+        \\ - calendarId: {s}
+        \\ - with day=3: {s}
+        \\ - toPlainDate(2024): {s}
+        \\ - toJSON(): {s}
+        \\ - toLocaleString(): {s}
+        \\ - valueOf supported: {}
+        \\
+        \\
+    , .{
+        try md_from.toString(allocator),
+        md.equals(md_from),
+        try md.calendarId(allocator),
+        try md_with.toString(allocator),
+        try md_date.toString(allocator, .{}),
+        try md.toJSON(allocator),
+        try md.toLocaleString(allocator),
+        md_valueof_supported,
+    });
+
+    const tm_from = try Temporal.PlainTime.from("13:45:30.123456789");
+    const tm_valueof_supported = tm.valueOf() != error.ValueError;
+    std.log.info(
+        \\PlainTime Coverage
+        \\ - from string: {s}
+        \\ - compare(tm, from): {}
+        \\ - millisecond/microsecond/nanosecond: {}/{}/{}
+        \\ - toJSON(): {s}
+        \\ - toLocaleString(): {s}
+        \\ - valueOf supported: {}
+        \\
+        \\
+    , .{
+        try tm_from.toString(allocator),
+        Temporal.PlainTime.compare(tm, tm_from),
+        tm.millisecond(),
+        tm.microsecond(),
+        tm.nanosecond(),
+        try tm.toJSON(allocator),
+        try tm.toLocaleString(allocator),
+        tm_valueof_supported,
+    });
+
+    const ym_from = try Temporal.PlainYearMonth.from("2024-02");
+    const ym_date = try ym.toPlainDate(2);
+    const ym_valueof_supported = ym.valueOf() != error.ValueError;
+    std.log.info(
+        \\PlainYearMonth Coverage
+        \\ - from string: {s}
+        \\ - compare(ym, from): {}
+        \\ - calendarId: {s}
+        \\ - monthCode: {s}
+        \\ - daysInMonth/daysInYear/monthsInYear: {}/{}/{}
+        \\ - inLeapYear: {}
+        \\ - era/eraYear: {any}/{?}
+        \\ - toPlainDate(2): {s}
+        \\ - toJSON(): {s}
+        \\ - toLocaleString(): {s}
+        \\ - valueOf supported: {}
+        \\
+        \\
+    , .{
+        try ym_from.toString(allocator),
+        Temporal.PlainYearMonth.compare(ym, ym_from),
+        try ym.calendarId(allocator),
+        try ym.monthCode(allocator),
+        ym.daysInMonth(),
+        ym.daysInYear(),
+        ym.monthsInYear(),
+        ym.inLeapYear(),
+        try ym.era(allocator),
+        ym.eraYear(),
+        try ym_date.toString(allocator, .{}),
+        try ym.toJSON(allocator),
+        try ym.toLocaleString(allocator),
+        ym_valueof_supported,
+    });
+
+    const zdt_init = try Temporal.ZonedDateTime.init(zdt_epoch_ns, tz);
+    const zdt_from_ms = try Temporal.ZonedDateTime.fromEpochMilliseconds(1_706_881_530_123, tz);
+    const zdt_from = try Temporal.ZonedDateTime.from("2024-02-02T13:45:30.123456789+00:00[UTC]", null, .compatible, .reject);
+    const zdt_transition_next = try zdt.getTimeZoneTransition(.next);
+    const zdt_transition_previous = try zdt.getTimeZoneTransition(.previous);
+    const zdt_day_start = try zdt.startOfDay();
+    const zdt_plain_date = try zdt.toPlainDate();
+    const zdt_plain_datetime = try zdt.toPlainDateTime();
+    const zdt_plain_time = try zdt.toPlainTime();
+    const zdt_valueof_supported = zdt.valueOf() != error.ValueOfNotSupported;
+    const zdt_with_supported = zdt.with(allocator, .{ .year = 2025 }) != error.TemporalNoteImplemented;
+    std.log.info(
+        \\ZonedDateTime Coverage
+        \\ - init: {s}
+        \\ - fromEpochMilliseconds: {s}
+        \\ - from string: {s}
+        \\ - compare(zdt, from): {}
+        \\ - next/previous transition exists: {}/{}
+        \\ - startOfDay: {s}
+        \\ - toJSON(): {s}
+        \\ - toLocaleString(): {s}
+        \\ - toPlainDate: {s}
+        \\ - toPlainDateTime: {s}
+        \\ - toPlainTime: {s}
+        \\ - calendarId: {s}
+        \\ - dayOfWeek/dayOfYear: {}/{}
+        \\ - daysInWeek/daysInMonth/daysInYear: {}/{}/{}
+        \\ - epochMilliseconds/epochNanoseconds: {}/{}
+        \\
+    , .{
+        try zdt_init.toString(allocator, .{}),
+        try zdt_from_ms.toString(allocator, .{}),
+        try zdt_from.toString(allocator, .{}),
+        Temporal.ZonedDateTime.compare(zdt, zdt_from),
+        zdt_transition_next != null,
+        zdt_transition_previous != null,
+        try zdt_day_start.toString(allocator, .{}),
+        try zdt.toJSON(allocator),
+        try zdt.toLocaleString(allocator),
+        try zdt_plain_date.toString(allocator, .{}),
+        try zdt_plain_datetime.toString(allocator, .{}),
+        try zdt_plain_time.toString(allocator),
+        try zdt.calendarId(allocator),
+        zdt.dayOfWeek(),
+        zdt.dayOfYear(),
+        zdt.daysInWeek(),
+        zdt.daysInMonth(),
+        zdt.daysInYear(),
+        zdt.epochMilliseconds(),
+        zdt.epochNanoseconds(),
+    });
+    std.log.info(
+        \\ZonedDateTime Coverage Continued
+        \\ - era/eraYear: {any}/{?}
+        \\ - hoursInDay/inLeapYear: {d}/{}
+        \\ - millisecond/microsecond/nanosecond: {}/{}/{}
+        \\ - monthCode/monthsInYear: {s}/{}
+        \\ - offset/offsetNanoseconds: {s}/{}
+        \\ - weekOfYear/yearOfWeek: {?}/{?}
+        \\ - valueOf supported: {}
+        \\ - with implemented: {}
+        \\
+        \\
+    , .{
+        try zdt.era(allocator),
+        zdt.eraYear(),
+        try zdt.hoursInDay(),
+        zdt.inLeapYear(),
+        zdt.millisecond(),
+        zdt.microsecond(),
+        zdt.nanosecond(),
+        try zdt.monthCode(allocator),
+        zdt.monthsInYear(),
+        try zdt.offset(allocator),
+        zdt.offsetNanoseconds(),
+        zdt.weekOfYear(),
+        zdt.yearOfWeek(),
+        zdt_valueof_supported,
+        zdt_with_supported,
+    });
 }
 
 extern fn consoleLog(ptr: [*]u8, len: u32) void;
diff --git a/src/Instant.zig b/src/Instant.zig
index 81565b7..a2b1b4c 100644
--- a/src/Instant.zig
+++ b/src/Instant.zig
@@ -3,6 +3,7 @@ const abi = @import("abi.zig");
 const t = @import("temporal.zig");
 
 const Duration = @import("Duration.zig");
+const ZonedDateTime = @import("ZonedDateTime.zig");
 
 /// The `Temporal.Instant` object represents a unique point in time, with nanosecond precision.
 /// It is fundamentally represented as the number of nanoseconds since the Unix epoch (midnight at the beginning of January 1, 1970, UTC), without any time zone or calendar system.
@@ -260,16 +261,6 @@ fn optsToRounding(opts: ToStringOptions) abi.c.ToStringRoundingOptions {
     };
 }
 
-// --- Forward declarations -----------------------------------------------------
-
-const ZonedDateTime = struct {
-    _inner: *abi.c.ZonedDateTime,
-
-    pub fn deinit(self: ZonedDateTime) void {
-        abi.c.temporal_rs_ZonedDateTime_destroy(self._inner);
-    }
-};
-
 // --- Tests -------------------------------------------------------------------
 
 test init {
diff --git a/src/PlainDate.zig b/src/PlainDate.zig
index 71b9733..64f4cd8 100644
--- a/src/PlainDate.zig
+++ b/src/PlainDate.zig
@@ -55,6 +55,22 @@ pub const ToZonedDateTimeOptions = struct {
     plain_time: ?PlainTime = null,
 };
 
+/// Options for `with()` method.
+pub const WithOptions = struct {
+    /// Year value to override.
+    year: ?i32 = null,
+    /// Month value to override.
+    month: ?u8 = null,
+    /// Calendar-specific month code to override.
+    month_code: ?[]const u8 = null,
+    /// Day value to override.
+    day: ?u8 = null,
+    /// Era value to override.
+    era: ?[]const u8 = null,
+    /// Era year value to override.
+    era_year: ?i32 = null,
+};
+
 /// Creates a new PlainDate from the given ISO year, month, and day.
 pub fn init(year_val: i32, month_val: u8, day_val: u8) !PlainDate {
     return calInit(year_val, month_val, day_val, "iso8601");
@@ -137,11 +153,28 @@ pub fn since(self: PlainDate, other: PlainDate, settings: DifferenceSettings) !D
     return .{ ._inner = ptr };
 }
 
-/// Returns a new PlainDate with some fields replaced (not implemented).
-pub fn with(self: PlainDate, fields: anytype) !PlainDate {
-    _ = self;
-    _ = fields;
-    return error.TemporalNotImplemented;
+/// Returns a new PlainDate with some fields replaced.
+pub fn with(self: PlainDate, fields: WithOptions) !PlainDate {
+    const partial_date = abi.c.PartialDate{
+        .year = if (fields.year) |y| abi.toOption(abi.c.OptionI32, y) else .{ .is_ok = false },
+        .month = if (fields.month) |m| abi.toOption(abi.c.OptionU8, m) else .{ .is_ok = false },
+        .day = if (fields.day) |d| abi.toOption(abi.c.OptionU8, d) else .{ .is_ok = false },
+        .month_code = if (fields.month_code) |mc| abi.toDiplomatStringView(mc) else .{ .data = null, .len = 0 },
+        .era = if (fields.era) |e| abi.toDiplomatStringView(e) else .{ .data = null, .len = 0 },
+        .era_year = if (fields.era_year) |ey| abi.toOption(abi.c.OptionI32, ey) else .{ .is_ok = false },
+        .calendar = abi.c.AnyCalendarKind_Iso,
+    };
+
+    const overflow = abi.c.ArithmeticOverflow_option{
+        .is_ok = true,
+        .unnamed_0 = .{ .ok = abi.c.ArithmeticOverflow_Constrain },
+    };
+
+    return wrapPlainDate(abi.c.temporal_rs_PlainDate_with(
+        self._inner,
+        partial_date,
+        overflow,
+    ));
 }
 
 /// Returns a new PlainDate with a different calendar.
@@ -526,7 +559,13 @@ test with {
     const date = try PlainDate.init(2024, 3, 15);
     defer date.deinit();
 
-    try std.testing.expectError(error.TemporalNotImplemented, date.with(.{}));
+    try std.testing.expectError(error.TypeError, date.with(.{}));
+
+    const changed = try date.with(.{ .year = 2025, .month = 4, .day = 16 });
+    defer changed.deinit();
+    try std.testing.expectEqual(@as(i32, 2025), changed.year());
+    try std.testing.expectEqual(@as(u8, 4), changed.month());
+    try std.testing.expectEqual(@as(u8, 16), changed.day());
 }
 
 test withCalendar {
diff --git a/src/root.zig b/src/root.zig
index d7b0e94..1daf15d 100644
--- a/src/root.zig
+++ b/src/root.zig
@@ -227,6 +227,7 @@ test PlainDate {
         "ToStringOptions",
         "CalendarDisplay",
         "ToZonedDateTimeOptions",
+        "WithOptions",
         "Unit",
         "RoundingMode",
         "Sign",
diff --git a/src/temporal.zig b/src/temporal.zig
index a463d8e..06f0e36 100644
--- a/src/temporal.zig
+++ b/src/temporal.zig
@@ -90,9 +90,11 @@ pub const TimeZone = struct {
     _inner: abi.c.TimeZone,
 
     /// Initialize a TimeZone from an identifier string.
-    pub fn init(id: []const u8) TimeZone {
+    pub fn init(id: []const u8) !TimeZone {
         const view = abi.toDiplomatStringView(id);
-        return .{ ._inner = .{ .id = view } };
+        const result = abi.c.temporal_rs_TimeZone_try_from_str(view);
+        const time_zone = try abi.extractResult(result);
+        return .{ ._inner = time_zone };
     }
 };