diff --git a/src/components/calendar.rs b/src/components/calendar.rs
index b8c82203e..66f453f49 100644
--- a/src/components/calendar.rs
+++ b/src/components/calendar.rs
@@ -35,6 +35,8 @@ use icu_calendar::{
 };
 use tinystr::TinyAsciiStr;
 
+use super::ZonedDateTime;
+
 /// The ECMAScript defined protocol methods
 pub const CALENDAR_PROTOCOL_METHODS: [&str; 21] = [
     "dateAdd",
@@ -618,6 +620,36 @@ impl Calendar {
     }
 }
 
+impl From<Date> for Calendar {
+    fn from(value: Date) -> Self {
+        value.calendar().clone()
+    }
+}
+
+impl From<DateTime> for Calendar {
+    fn from(value: DateTime) -> Self {
+        value.calendar().clone()
+    }
+}
+
+impl From<ZonedDateTime> for Calendar {
+    fn from(value: ZonedDateTime) -> Self {
+        value.calendar().clone()
+    }
+}
+
+impl From<MonthDay> for Calendar {
+    fn from(value: MonthDay) -> Self {
+        value.calendar().clone()
+    }
+}
+
+impl From<YearMonth> for Calendar {
+    fn from(value: YearMonth) -> Self {
+        value.calendar().clone()
+    }
+}
+
 #[cfg(all(test, feature = "compiled_data"))]
 mod tests {
     use super::*;
diff --git a/src/components/date.rs b/src/components/date.rs
index f6c62c5b5..51802103a 100644
--- a/src/components/date.rs
+++ b/src/components/date.rs
@@ -193,13 +193,15 @@ impl Date {
         Ok(Self::new_unchecked(iso, calendar))
     }
 
-    #[must_use]
-    /// Creates a `Date` from a `DateTime`.
-    pub fn from_datetime(dt: &DateTime) -> Self {
-        Self {
-            iso: dt.iso_date(),
-            calendar: dt.calendar().clone(),
-        }
+    /// Creates a new `Date` from the current `Date` and the provided calendar.
+    pub fn with_calendar(&self, calendar: Calendar) -> TemporalResult<Self> {
+        Self::new(
+            self.iso_year(),
+            self.iso_month().into(),
+            self.iso_day().into(),
+            calendar,
+            ArithmeticOverflow::Reject,
+        )
     }
 
     #[inline]
diff --git a/src/components/datetime.rs b/src/components/datetime.rs
index aa7caca9a..2d5b21e6b 100644
--- a/src/components/datetime.rs
+++ b/src/components/datetime.rs
@@ -14,7 +14,7 @@ use tinystr::TinyAsciiStr;
 use super::{
     calendar::{CalendarDateLike, GetTemporalCalendar},
     duration::normalized::{NormalizedTimeDuration, RelativeRoundResult},
-    Date, Duration,
+    Date, Duration, Time,
 };
 
 /// The native Rust implementation of `Temporal.PlainDateTime`
@@ -191,6 +191,38 @@ impl DateTime {
         ))
     }
 
+    /// Creates a new `DateTime` from the current `DateTime` and the provided `Time`.
+    pub fn with_time(&self, time: Time) -> TemporalResult<Self> {
+        Self::new(
+            self.iso_year(),
+            self.iso_month().into(),
+            self.iso_day().into(),
+            time.hour().into(),
+            time.minute().into(),
+            time.second().into(),
+            time.millisecond().into(),
+            time.microsecond().into(),
+            time.nanosecond().into(),
+            self.calendar.clone(),
+        )
+    }
+
+    /// Creates a new `DateTime` from the current `DateTime` and a provided `Calendar`.
+    pub fn with_calendar(&self, calendar: Calendar) -> TemporalResult<Self> {
+        Self::new(
+            self.iso_year(),
+            self.iso_month().into(),
+            self.iso_day().into(),
+            self.hour().into(),
+            self.minute().into(),
+            self.second().into(),
+            self.millisecond().into(),
+            self.microsecond().into(),
+            self.nanosecond().into(),
+            calendar,
+        )
+    }
+
     /// Validates whether ISO date slots are within iso limits at noon.
     #[inline]
     pub fn validate<T: IsoDateSlots>(target: &T) -> bool {