diff --git a/src/java.base/share/classes/sun/nio/cs/UTF_32Coder.java b/src/java.base/share/classes/sun/nio/cs/UTF_32Coder.java
index c6f38ec9bfc..72e59d22e2c 100644
--- a/src/java.base/share/classes/sun/nio/cs/UTF_32Coder.java
+++ b/src/java.base/share/classes/sun/nio/cs/UTF_32Coder.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2005, 2026, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -185,5 +185,12 @@ class UTF_32Coder {
             doneBOM = !doBOM;
         }
 
+        public boolean canEncode(char c) {
+            return !Character.isSurrogate(c);
+        }
+
+        public boolean canEncode(CharSequence cs) {
+            return Unicode.isValidUnicode(cs);
+        }
     }
 }
diff --git a/src/java.base/share/classes/sun/nio/cs/UTF_8.java b/src/java.base/share/classes/sun/nio/cs/UTF_8.java
index 2928ae6d509..fda8e5eec1f 100644
--- a/src/java.base/share/classes/sun/nio/cs/UTF_8.java
+++ b/src/java.base/share/classes/sun/nio/cs/UTF_8.java
@@ -424,6 +424,10 @@ public final class UTF_8 extends Unicode {
             return !Character.isSurrogate(c);
         }
 
+        public boolean canEncode(CharSequence cs) {
+            return Unicode.isValidUnicode(cs);
+        }
+
         public boolean isLegalReplacement(byte[] repl) {
             return ((repl.length == 1 && repl[0] >= 0) ||
                     super.isLegalReplacement(repl));
diff --git a/src/java.base/share/classes/sun/nio/cs/Unicode.java b/src/java.base/share/classes/sun/nio/cs/Unicode.java
index aac77a13ffb..06a50f125c5 100644
--- a/src/java.base/share/classes/sun/nio/cs/Unicode.java
+++ b/src/java.base/share/classes/sun/nio/cs/Unicode.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2005, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2005, 2026, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -95,4 +95,23 @@ abstract class Unicode extends Charset
                 || (cs.name().equals("x-Johab"))
                 || (cs.name().equals("Shift_JIS")));
     }
+
+    static boolean isValidUnicode(CharSequence cs) {
+        int length = cs.length();
+        for (int i = 0; i < length;) {
+            char c = cs.charAt(i++);
+            if (Character.isHighSurrogate(c)) {
+                if (i == length) {
+                    return false;
+                }
+                char low = cs.charAt(i++);
+                if (!Character.isLowSurrogate(low)) {
+                    return false;
+                }
+            } else if (Character.isLowSurrogate(c)) {
+                return false;
+            }
+        }
+        return true;
+    }
 }
diff --git a/src/java.base/share/classes/sun/nio/cs/UnicodeEncoder.java b/src/java.base/share/classes/sun/nio/cs/UnicodeEncoder.java
index 7b34fb2d512..6f7413dcbf8 100644
--- a/src/java.base/share/classes/sun/nio/cs/UnicodeEncoder.java
+++ b/src/java.base/share/classes/sun/nio/cs/UnicodeEncoder.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2026, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -108,4 +108,8 @@ public abstract class UnicodeEncoder extends CharsetEncoder {
     public boolean canEncode(char c) {
         return ! Character.isSurrogate(c);
     }
+
+    public boolean canEncode(CharSequence cs) {
+        return Unicode.isValidUnicode(cs);
+    }
 }
diff --git a/test/jdk/java/nio/charset/CharsetEncoder/CanEncode.java b/test/jdk/java/nio/charset/CharsetEncoder/CanEncode.java
index 8545ef61be9..d4dabf70910 100644
--- a/test/jdk/java/nio/charset/CharsetEncoder/CanEncode.java
+++ b/test/jdk/java/nio/charset/CharsetEncoder/CanEncode.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2010, 2026, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -66,14 +66,21 @@ public class CanEncode {
         Charset cs = Charset.forName(csn);
         CharsetEncoder ce = cs.newEncoder();
 
-        if (cs.name().equals("US-ASCII")) {
-            ck(ce, 'x', true);
-            ck(ce, '\u00B6', false);
-            ck(ce, "x", true);
-            ck(ce, "\u00B6", false);
-            ck(ce, "xyzzy", true);
-            ck(ce, "xy\u00B6", false);
-        }
+        // Basic multilingual plane
+        boolean utf = csn.startsWith("UTF-");
+        ck(ce, 'x', true);
+        ck(ce, '\u00B6', utf);
+        ck(ce, "", true);
+        ck(ce, "x", true);
+        ck(ce, "\u00B6", utf);
+        ck(ce, "xyzzy", true);
+        ck(ce, "xy\u00B6", utf);
+
+        // Paired surrogates
+        ck(ce, "\uD83D\uDE00", utf);
+        ck(ce, "XX\uD83D\uDE00", utf);
+        ck(ce, "\uD83D\uDE00XX", utf);
+        ck(ce, "X\uD83D\uDE00X", utf);
 
         // Unpaired surrogates should never be encodable
         ck(ce, '\ud800', false);
@@ -81,15 +88,36 @@ public class CanEncode {
         ck(ce, '\udffe', false);
         ck(ce, '\udfff', false);
         ck(ce, "\ud800", false);
+        ck(ce, "XX\ud800", false);
+        ck(ce, "\ud800XX", false);
+        ck(ce, "X\ud800X", false);
         ck(ce, "\ud801", false);
+        ck(ce, "XX\ud801", false);
+        ck(ce, "\ud801XX", false);
+        ck(ce, "X\ud801X", false);
         ck(ce, "\udffe", false);
+        ck(ce, "XX\udffe", false);
+        ck(ce, "\udffeXX", false);
+        ck(ce, "X\udffeX", false);
         ck(ce, "\udfff", false);
+        ck(ce, "XX\udfff", false);
+        ck(ce, "\udfffXX", false);
+        ck(ce, "X\udfffX", false);
 
+        if (errors > 0) {
+            throw new RuntimeException(errors + " errors for Charset " + csn);
+        }
     }
 
     public static void main(String[] args) throws Exception {
         test("US-ASCII");
         test("UTF-8");
+        test("UTF-16");
+        test("UTF-16LE");
+        test("UTF-16BE");
+        test("UTF-32");
+        test("UTF-32LE");
+        test("UTF-32BE");
     }
 
 }
diff --git a/test/micro/org/openjdk/bench/java/nio/CharsetCanEncode.java b/test/micro/org/openjdk/bench/java/nio/CharsetCanEncode.java
index ebfbc217a95..8c08a876696 100644
--- a/test/micro/org/openjdk/bench/java/nio/CharsetCanEncode.java
+++ b/test/micro/org/openjdk/bench/java/nio/CharsetCanEncode.java
@@ -65,6 +65,9 @@ public class CharsetCanEncode {
     // sun.nio.cs.UTF_16LE
     private CharsetEncoder utf16le = Charset.forName("UTF-16LE").newEncoder();
 
+    // sun.nio.cs.UTF_32LE
+    private CharsetEncoder utf32le = Charset.forName("UTF-32LE").newEncoder();
+
     @Benchmark
     public boolean asciiCanEncodeCharYes() {
         return ascii.canEncode('D');
@@ -184,4 +187,24 @@ public class CharsetCanEncode {
     public boolean utf16leCanEncodeStringNo() {
         return utf16le.canEncode(String.valueOf(Character.MIN_SURROGATE));
     }
+
+    @Benchmark
+    public boolean utf32leCanEncodeCharYes() {
+        return utf32le.canEncode('D');
+    }
+
+    @Benchmark
+    public boolean utf32leCanEncodeStringYes() {
+        return utf32le.canEncode("D");
+    }
+
+    @Benchmark
+    public boolean utf32leCanEncodeCharNo() {
+        return utf32le.canEncode(Character.MIN_SURROGATE);
+    }
+
+    @Benchmark
+    public boolean utf32leCanEncodeStringNo() {
+        return utf32le.canEncode(String.valueOf(Character.MIN_SURROGATE));
+    }
 }