diff --git a/spring-web/src/main/java/org/springframework/web/server/adapter/ForwardedHeaderTransformer.java b/spring-web/src/main/java/org/springframework/web/server/adapter/ForwardedHeaderTransformer.java
index 0903f38a6f..5e33e6d7c7 100644
--- a/spring-web/src/main/java/org/springframework/web/server/adapter/ForwardedHeaderTransformer.java
+++ b/spring-web/src/main/java/org/springframework/web/server/adapter/ForwardedHeaderTransformer.java
@@ -18,6 +18,7 @@ package org.springframework.web.server.adapter;
 
 import java.net.InetSocketAddress;
 import java.net.URI;
+import java.net.URISyntaxException;
 import java.util.Collections;
 import java.util.Locale;
 import java.util.Set;
@@ -30,6 +31,7 @@ import org.springframework.lang.Nullable;
 import org.springframework.util.LinkedCaseInsensitiveMap;
 import org.springframework.util.StringUtils;
 import org.springframework.web.util.ForwardedHeaderUtils;
+import org.springframework.web.util.UriComponents;
 
 /**
  * Extract values from "Forwarded" and "X-Forwarded-*" headers to override
@@ -102,7 +104,7 @@ public class ForwardedHeaderTransformer implements Function<ServerHttpRequest, S
 			if (!this.removeOnly) {
 				URI originalUri = request.getURI();
 				HttpHeaders headers = request.getHeaders();
-				URI uri = ForwardedHeaderUtils.adaptFromForwardedHeaders(originalUri, headers).build(true).toUri();
+				URI uri = adaptFromForwardedHeaders(originalUri, headers);
 				builder.uri(uri);
 				String prefix = getForwardedPrefix(request);
 				if (prefix != null) {
@@ -121,6 +123,17 @@ public class ForwardedHeaderTransformer implements Function<ServerHttpRequest, S
 		return request;
 	}
 
+	private static URI adaptFromForwardedHeaders(URI uri, HttpHeaders headers) {
+		// GH-30137: assume URI is encoded, but avoid build(true) for more lenient handling
+		UriComponents components = ForwardedHeaderUtils.adaptFromForwardedHeaders(uri, headers).build();
+		try {
+			return new URI(components.toUriString());
+		}
+		catch (URISyntaxException ex) {
+			throw new IllegalStateException("Could not create URI object: " + ex.getMessage(), ex);
+		}
+	}
+
 	/**
 	 * Whether the request has any Forwarded headers.
 	 * @param request the request
diff --git a/spring-web/src/test/java/org/springframework/web/server/adapter/ForwardedHeaderTransformerTests.java b/spring-web/src/test/java/org/springframework/web/server/adapter/ForwardedHeaderTransformerTests.java
index d1f66abe9c..68d2464294 100644
--- a/spring-web/src/test/java/org/springframework/web/server/adapter/ForwardedHeaderTransformerTests.java
+++ b/spring-web/src/test/java/org/springframework/web/server/adapter/ForwardedHeaderTransformerTests.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-202 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -57,7 +57,7 @@ class ForwardedHeaderTransformerTests {
 	}
 
 	@Test
-	void xForwardedHeaders() throws Exception {
+	void xForwardedHeaders() {
 		HttpHeaders headers = new HttpHeaders();
 		headers.add("X-Forwarded-Host", "84.198.58.199");
 		headers.add("X-Forwarded-Port", "443");
@@ -70,7 +70,7 @@ class ForwardedHeaderTransformerTests {
 	}
 
 	@Test
-	void forwardedHeader() throws Exception {
+	void forwardedHeader() {
 		HttpHeaders headers = new HttpHeaders();
 		headers.add("Forwarded", "host=84.198.58.199;proto=https");
 		ServerHttpRequest request = this.requestMutator.apply(getRequest(headers));
@@ -80,7 +80,7 @@ class ForwardedHeaderTransformerTests {
 	}
 
 	@Test
-	void xForwardedPrefix() throws Exception {
+	void xForwardedPrefix() {
 		HttpHeaders headers = new HttpHeaders();
 		headers.add("X-Forwarded-Prefix", "/prefix");
 		ServerHttpRequest request = this.requestMutator.apply(getRequest(headers));
@@ -91,7 +91,7 @@ class ForwardedHeaderTransformerTests {
 	}
 
 	@Test // gh-23305
-	void xForwardedPrefixShouldNotLeadToDecodedPath() throws Exception {
+	void xForwardedPrefixShouldNotLeadToDecodedPath() {
 		HttpHeaders headers = new HttpHeaders();
 		headers.add("X-Forwarded-Prefix", "/prefix");
 		ServerHttpRequest request = MockServerHttpRequest
@@ -107,7 +107,7 @@ class ForwardedHeaderTransformerTests {
 	}
 
 	@Test
-	void xForwardedPrefixTrailingSlash() throws Exception {
+	void xForwardedPrefixTrailingSlash() {
 		HttpHeaders headers = new HttpHeaders();
 		headers.add("X-Forwarded-Prefix", "/prefix////");
 		ServerHttpRequest request = this.requestMutator.apply(getRequest(headers));
@@ -118,7 +118,7 @@ class ForwardedHeaderTransformerTests {
 	}
 
 	@Test // SPR-17525
-	void shouldNotDoubleEncode() throws Exception {
+	void shouldNotDoubleEncode() {
 		HttpHeaders headers = new HttpHeaders();
 		headers.add("Forwarded", "host=84.198.58.199;proto=https");
 
@@ -133,8 +133,8 @@ class ForwardedHeaderTransformerTests {
 		assertForwardedHeadersRemoved(request);
 	}
 
-	@Test
-	void shouldHandleUnencodedUri() throws Exception {
+	@Test // gh-30137
+	void shouldHandleUnencodedUri() {
 			HttpHeaders headers = new HttpHeaders();
 			headers.add("Forwarded", "host=84.198.58.199;proto=https");
 			ServerHttpRequest request = MockServerHttpRequest
@@ -149,7 +149,7 @@ class ForwardedHeaderTransformerTests {
 	}
 
 	@Test
-	void shouldConcatenatePrefixes() throws Exception {
+	void shouldConcatenatePrefixes() {
 		HttpHeaders headers = new HttpHeaders();
 		headers.add("X-Forwarded-Prefix", "/first,/second");
 		ServerHttpRequest request = this.requestMutator.apply(getRequest(headers));
@@ -160,7 +160,7 @@ class ForwardedHeaderTransformerTests {
 	}
 
 	@Test
-	void shouldConcatenatePrefixesWithTrailingSlashes() throws Exception {
+	void shouldConcatenatePrefixesWithTrailingSlashes() {
 		HttpHeaders headers = new HttpHeaders();
 		headers.add("X-Forwarded-Prefix", "/first/,/second//");
 		ServerHttpRequest request = this.requestMutator.apply(getRequest(headers));