diff --git a/src/encoding/json/internal/jsonflags/flags.go b/src/encoding/json/internal/jsonflags/flags.go
index 4496359c89..1e8c2842d4 100644
--- a/src/encoding/json/internal/jsonflags/flags.go
+++ b/src/encoding/json/internal/jsonflags/flags.go
@@ -52,7 +52,6 @@ const (
 		AllowInvalidUTF8 |
 		EscapeForHTML |
 		EscapeForJS |
-		EscapeInvalidUTF8 |
 		PreserveRawStrings |
 		Deterministic |
 		FormatNilMapAsNull |
@@ -77,7 +76,7 @@ const (
 	WhitespaceFlags = AnyWhitespace | Indent | IndentPrefix
 
 	// AnyEscape is the set of flags related to escaping in a JSON string.
-	AnyEscape = EscapeForHTML | EscapeForJS | EscapeInvalidUTF8
+	AnyEscape = EscapeForHTML | EscapeForJS
 
 	// CanonicalizeNumbers is the set of flags related to raw number canonicalization.
 	CanonicalizeNumbers = CanonicalizeRawInts | CanonicalizeRawFloats
@@ -97,7 +96,6 @@ const (
 	ReorderRawObjects     // encode only
 	EscapeForHTML         // encode only
 	EscapeForJS           // encode only
-	EscapeInvalidUTF8     // encode only; only exposed in v1
 	Multiline             // encode only
 	SpaceAfterColon       // encode only
 	SpaceAfterComma       // encode only
diff --git a/src/encoding/json/internal/jsonwire/encode.go b/src/encoding/json/internal/jsonwire/encode.go
index 3901ff8bed..8f9b8ab09e 100644
--- a/src/encoding/json/internal/jsonwire/encode.go
+++ b/src/encoding/json/internal/jsonwire/encode.go
@@ -92,11 +92,7 @@ func AppendQuote[Bytes ~[]byte | ~string](dst []byte, src Bytes, flags *jsonflag
 			case isInvalidUTF8(r, rn):
 				hasInvalidUTF8 = true
 				dst = append(dst, src[i:n-rn]...)
-				if flags.Get(jsonflags.EscapeInvalidUTF8) {
-					dst = append(dst, `\ufffd`...)
-				} else {
-					dst = append(dst, "\ufffd"...)
-				}
+				dst = append(dst, "\ufffd"...)
 				i = n
 			case (r == '\u2028' || r == '\u2029') && flags.Get(jsonflags.EscapeForJS):
 				dst = append(dst, src[i:n-rn]...)
diff --git a/src/encoding/json/v2_decode_test.go b/src/encoding/json/v2_decode_test.go
index cfcefbfcdc..1e4914efc4 100644
--- a/src/encoding/json/v2_decode_test.go
+++ b/src/encoding/json/v2_decode_test.go
@@ -1249,12 +1249,12 @@ func TestMarshalInvalidUTF8(t *testing.T) {
 		in   string
 		want string
 	}{
-		{Name(""), "hello\xffworld", `"hello\ufffdworld"`},
+		{Name(""), "hello\xffworld", "\"hello\ufffdworld\""},
 		{Name(""), "", `""`},
-		{Name(""), "\xff", `"\ufffd"`},
-		{Name(""), "\xff\xff", `"\ufffd\ufffd"`},
-		{Name(""), "a\xffb", `"a\ufffdb"`},
-		{Name(""), "\xe6\x97\xa5\xe6\x9c\xac\xff\xaa\x9e", `"日本\ufffd\ufffd\ufffd"`},
+		{Name(""), "\xff", "\"\ufffd\""},
+		{Name(""), "\xff\xff", "\"\ufffd\ufffd\""},
+		{Name(""), "a\xffb", "\"a\ufffdb\""},
+		{Name(""), "\xe6\x97\xa5\xe6\x9c\xac\xff\xaa\x9e", "\"日本\ufffd\ufffd\ufffd\""},
 	}
 	for _, tt := range tests {
 		t.Run(tt.Name, func(t *testing.T) {
diff --git a/src/encoding/json/v2_diff_test.go b/src/encoding/json/v2_diff_test.go
index 7a561732f4..9d0798ed1d 100644
--- a/src/encoding/json/v2_diff_test.go
+++ b/src/encoding/json/v2_diff_test.go
@@ -786,8 +786,8 @@ func TestInvalidUTF8(t *testing.T) {
 			switch {
 			case json.Version == "v1" && err != nil:
 				t.Fatalf("json.Marshal error: %v", err)
-			case json.Version == "v1" && string(got) != `"\ufffd"`:
-				t.Fatalf(`json.Marshal = %s, want "\ufffd"`, got)
+			case json.Version == "v1" && string(got) != "\"\ufffd\"":
+				t.Fatalf(`json.Marshal = %s, want %q`, got, "\ufffd")
 			case json.Version == "v2" && err == nil:
 				t.Fatal("json.Marshal error is nil, want non-nil")
 			}
diff --git a/src/encoding/json/v2_options.go b/src/encoding/json/v2_options.go
index 4006d764cc..66bd01eb3c 100644
--- a/src/encoding/json/v2_options.go
+++ b/src/encoding/json/v2_options.go
@@ -204,7 +204,6 @@ type Options = jsonopts.Options
 // It is equivalent to the following boolean options being set to true:
 //
 //   - [CallMethodsWithLegacySemantics]
-//   - [EscapeInvalidUTF8]
 //   - [FormatBytesWithLegacySemantics]
 //   - [FormatTimeWithLegacySemantics]
 //   - [MatchCaseSensitiveDelimiter]
@@ -279,23 +278,6 @@ func CallMethodsWithLegacySemantics(v bool) Options {
 	}
 }
 
-// EscapeInvalidUTF8 specifies that when encoding a [jsontext.String]
-// with bytes of invalid UTF-8, such bytes are escaped as
-// a hexadecimal Unicode codepoint (i.e., \ufffd).
-// In contrast, the v2 default is to use the minimal representation,
-// which is to encode invalid UTF-8 as the Unicode replacement rune itself
-// (without any form of escaping).
-//
-// This only affects encoding and is ignored when decoding.
-// The v1 default is true.
-func EscapeInvalidUTF8(v bool) Options {
-	if v {
-		return jsonflags.EscapeInvalidUTF8 | 1
-	} else {
-		return jsonflags.EscapeInvalidUTF8 | 0
-	}
-}
-
 // FormatBytesWithLegacySemantics specifies that handling of
 // []~byte and [N]~byte types follow legacy semantics:
 //