diff --git a/js/public/friend/ErrorNumbers.msg b/js/public/friend/ErrorNumbers.msg
index 838f70a6540b..725e0753a2e5 100644
--- a/js/public/friend/ErrorNumbers.msg
+++ b/js/public/friend/ErrorNumbers.msg
@@ -14668,6 +14668,38 @@ seconds
 precision
 "
 )
+MSG_DEF
+(
+JSMSG_TEMPORAL_PARSER_INCONSISTENT_DATE_SEPARATOR
+0
+JSEXN_RANGEERR
+"
+date
+separator
+'
+-
+'
+must
+be
+consistent
+"
+)
+MSG_DEF
+(
+JSMSG_TEMPORAL_PARSER_INCONSISTENT_TIME_SEPARATOR
+0
+JSEXN_RANGEERR
+"
+time
+separator
+'
+:
+'
+must
+be
+consistent
+"
+)
 /
 /
 Explicit
diff --git a/js/src/builtin/temporal/TemporalParser.cpp b/js/src/builtin/temporal/TemporalParser.cpp
index 06ac93a6f396..dad704da30fc 100644
--- a/js/src/builtin/temporal/TemporalParser.cpp
+++ b/js/src/builtin/temporal/TemporalParser.cpp
@@ -6114,6 +6114,9 @@ JSMSG_TEMPORAL_PARSER_MISSING_YEAR
 Optional
 :
 -
+bool
+hasMonthSeparator
+=
 character
 (
 '
@@ -6202,6 +6205,9 @@ JSMSG_TEMPORAL_PARSER_MISSING_MONTH
 Optional
 :
 -
+bool
+hasDaySeparator
+=
 character
 (
 '
@@ -6211,6 +6217,32 @@ character
 ;
 /
 /
+Date
+separators
+must
+be
+consistent
+.
+if
+(
+hasMonthSeparator
+!
+=
+hasDaySeparator
+)
+{
+return
+mozilla
+:
+:
+Err
+(
+JSMSG_TEMPORAL_PARSER_INCONSISTENT_DATE_SEPARATOR
+)
+;
+}
+/
+/
 DateDay
 :
 :
@@ -6457,7 +6489,7 @@ Optional
 :
 :
 bool
-needsMinutes
+hasMinuteSeparator
 =
 character
 (
@@ -6557,11 +6589,8 @@ Optional
 :
 :
 bool
-needsSeconds
+hasSecondSeparator
 =
-needsMinutes
-&
-&
 character
 (
 '
@@ -6627,6 +6656,32 @@ JSMSG_TEMPORAL_PARSER_INVALID_LEAPSECOND
 }
 /
 /
+Time
+separators
+must
+be
+consistent
+.
+if
+(
+hasMinuteSeparator
+!
+=
+hasSecondSeparator
+)
+{
+return
+mozilla
+:
+:
+Err
+(
+JSMSG_TEMPORAL_PARSER_INCONSISTENT_TIME_SEPARATOR
+)
+;
+}
+/
+/
 TimeFraction
 :
 :
@@ -6698,7 +6753,7 @@ fractionalPart
 else
 if
 (
-needsSeconds
+hasSecondSeparator
 )
 {
 return
@@ -6715,7 +6770,7 @@ JSMSG_TEMPORAL_PARSER_MISSING_SECOND
 else
 if
 (
-needsMinutes
+hasMinuteSeparator
 )
 {
 return
@@ -7431,7 +7486,7 @@ Extended
 empty
 ]
 bool
-needsMinutes
+hasMinuteSeparator
 =
 character
 (
@@ -7540,11 +7595,8 @@ Extended
 empty
 ]
 bool
-needsSeconds
+hasSecondSeparator
 =
-needsMinutes
-&
-&
 character
 (
 '
@@ -7626,6 +7678,32 @@ JSMSG_TEMPORAL_PARSER_INVALID_SECOND
 )
 ;
 }
+/
+/
+Time
+separators
+must
+be
+consistent
+.
+if
+(
+hasMinuteSeparator
+!
+=
+hasSecondSeparator
+)
+{
+return
+mozilla
+:
+:
+Err
+(
+JSMSG_TEMPORAL_PARSER_INCONSISTENT_TIME_SEPARATOR
+)
+;
+}
 if
 (
 auto
@@ -7657,7 +7735,7 @@ true
 else
 if
 (
-needsSeconds
+hasSecondSeparator
 )
 {
 return
@@ -7674,7 +7752,7 @@ JSMSG_TEMPORAL_PARSER_MISSING_SECOND
 else
 if
 (
-needsMinutes
+hasMinuteSeparator
 )
 {
 return