diff --git a/Userland/Libraries/LibJS/Runtime/Temporal/Instant.cpp b/Userland/Libraries/LibJS/Runtime/Temporal/Instant.cpp
index 9eef0ae6ec..2533434491 100644
--- a/Userland/Libraries/LibJS/Runtime/Temporal/Instant.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Temporal/Instant.cpp
@@ -275,7 +275,7 @@ ThrowCompletionOr<String> temporal_instant_to_string(VM& vm, Instant& instant, V
         auto offset_ns = TRY(get_offset_nanoseconds_for(vm, time_zone, instant));
 
         // b. Let timeZoneString be ! FormatISOTimeZoneOffsetString(offsetNs).
-        time_zone_string = TRY_OR_THROW_OOM(vm, String::from_deprecated_string(format_iso_time_zone_offset_string(offset_ns)));
+        time_zone_string = MUST_OR_THROW_OOM(format_iso_time_zone_offset_string(vm, offset_ns));
     }
 
     // 10. Return the string-concatenation of dateTimeString and timeZoneString.
diff --git a/Userland/Libraries/LibJS/Runtime/Temporal/TimeZone.cpp b/Userland/Libraries/LibJS/Runtime/Temporal/TimeZone.cpp
index 3ca6fe794b..90678659a2 100644
--- a/Userland/Libraries/LibJS/Runtime/Temporal/TimeZone.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Temporal/TimeZone.cpp
@@ -264,7 +264,7 @@ ThrowCompletionOr<String> format_time_zone_offset_string(VM& vm, double offset_n
 }
 
 // 11.6.6 FormatISOTimeZoneOffsetString ( offsetNanoseconds ), https://tc39.es/proposal-temporal/#sec-temporal-formatisotimezoneoffsetstring
-DeprecatedString format_iso_time_zone_offset_string(double offset_nanoseconds)
+ThrowCompletionOr<String> format_iso_time_zone_offset_string(VM& vm, double offset_nanoseconds)
 {
     // 1. Assert: offsetNanoseconds is an integer.
     VERIFY(trunc(offset_nanoseconds) == offset_nanoseconds);
@@ -287,7 +287,7 @@ DeprecatedString format_iso_time_zone_offset_string(double offset_nanoseconds)
     // 7. Let h be ToZeroPaddedDecimalString(hours, 2).
     // 8. Let m be ToZeroPaddedDecimalString(minutes, 2).
     // 9. Return the string-concatenation of sign, h, the code unit 0x003A (COLON), and m.
-    return DeprecatedString::formatted("{}{:02}:{:02}", sign, (u32)hours, (u32)minutes);
+    return TRY_OR_THROW_OOM(vm, String::formatted("{}{:02}:{:02}", sign, (u32)hours, (u32)minutes));
 }
 
 // 11.6.7 ToTemporalTimeZone ( temporalTimeZoneLike ), https://tc39.es/proposal-temporal/#sec-temporal-totemporaltimezone
diff --git a/Userland/Libraries/LibJS/Runtime/Temporal/TimeZone.h b/Userland/Libraries/LibJS/Runtime/Temporal/TimeZone.h
index a091d97129..51eb689857 100644
--- a/Userland/Libraries/LibJS/Runtime/Temporal/TimeZone.h
+++ b/Userland/Libraries/LibJS/Runtime/Temporal/TimeZone.h
@@ -43,7 +43,7 @@ ISODateTime get_iso_parts_from_epoch(VM&, Crypto::SignedBigInteger const& epoch_
 BigInt* get_named_time_zone_next_transition(VM&, StringView time_zone_identifier, BigInt const& epoch_nanoseconds);
 BigInt* get_named_time_zone_previous_transition(VM&, StringView time_zone_identifier, BigInt const& epoch_nanoseconds);
 ThrowCompletionOr<String> format_time_zone_offset_string(VM&, double offset_nanoseconds);
-DeprecatedString format_iso_time_zone_offset_string(double offset_nanoseconds);
+ThrowCompletionOr<String> format_iso_time_zone_offset_string(VM&, double offset_nanoseconds);
 ThrowCompletionOr<Object*> to_temporal_time_zone(VM&, Value temporal_time_zone_like);
 ThrowCompletionOr<double> get_offset_nanoseconds_for(VM&, Value time_zone, Instant&);
 ThrowCompletionOr<DeprecatedString> builtin_time_zone_get_offset_string_for(VM&, Value time_zone, Instant&);
diff --git a/Userland/Libraries/LibJS/Runtime/Temporal/ZonedDateTime.cpp b/Userland/Libraries/LibJS/Runtime/Temporal/ZonedDateTime.cpp
index 7bcb80874c..648ad11a33 100644
--- a/Userland/Libraries/LibJS/Runtime/Temporal/ZonedDateTime.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Temporal/ZonedDateTime.cpp
@@ -314,12 +314,12 @@ ThrowCompletionOr<DeprecatedString> temporal_zoned_date_time_to_string(VM& vm, Z
     // 9. Let dateTimeString be ! TemporalDateTimeToString(temporalDateTime.[[ISOYear]], temporalDateTime.[[ISOMonth]], temporalDateTime.[[ISODay]], temporalDateTime.[[ISOHour]], temporalDateTime.[[ISOMinute]], temporalDateTime.[[ISOSecond]], temporalDateTime.[[ISOMillisecond]], temporalDateTime.[[ISOMicrosecond]], temporalDateTime.[[ISONanosecond]], isoCalendar, precision, "never").
     auto date_time_string = MUST_OR_THROW_OOM(temporal_date_time_to_string(vm, temporal_date_time->iso_year(), temporal_date_time->iso_month(), temporal_date_time->iso_day(), temporal_date_time->iso_hour(), temporal_date_time->iso_minute(), temporal_date_time->iso_second(), temporal_date_time->iso_millisecond(), temporal_date_time->iso_microsecond(), temporal_date_time->iso_nanosecond(), iso_calendar, precision, "never"sv));
 
-    DeprecatedString offset_string;
+    String offset_string;
 
     // 10. If showOffset is "never", then
     if (show_offset == "never"sv) {
         // a. Let offsetString be the empty String.
-        offset_string = DeprecatedString::empty();
+        offset_string = {};
     }
     // 11. Else,
     else {
@@ -327,7 +327,7 @@ ThrowCompletionOr<DeprecatedString> temporal_zoned_date_time_to_string(VM& vm, Z
         auto offset_ns = TRY(get_offset_nanoseconds_for(vm, &time_zone, *instant));
 
         // b. Let offsetString be ! FormatISOTimeZoneOffsetString(offsetNs).
-        offset_string = format_iso_time_zone_offset_string(offset_ns);
+        offset_string = MUST_OR_THROW_OOM(format_iso_time_zone_offset_string(vm, offset_ns));
     }
 
     DeprecatedString time_zone_string;