diff --git a/okhttp/src/commonJvmAndroid/kotlin/okhttp3/internal/connection/RealRoutePlanner.kt b/okhttp/src/commonJvmAndroid/kotlin/okhttp3/internal/connection/RealRoutePlanner.kt
index 132d5b3f0f49..1bebefe00910 100644
--- a/okhttp/src/commonJvmAndroid/kotlin/okhttp3/internal/connection/RealRoutePlanner.kt
+++ b/okhttp/src/commonJvmAndroid/kotlin/okhttp3/internal/connection/RealRoutePlanner.kt
@@ -348,6 +348,8 @@ class RealRoutePlanner internal constructor(
 
   override fun sameHostAndPort(url: HttpUrl): Boolean {
     val routeUrl = address.url
-    return url.port == routeUrl.port && url.host == routeUrl.host
+    return url.port == routeUrl.port &&
+      url.host == routeUrl.host &&
+      url.scheme == routeUrl.scheme
   }
 }
diff --git a/okhttp/src/commonJvmAndroid/kotlin/okhttp3/internal/connection/RoutePlanner.kt b/okhttp/src/commonJvmAndroid/kotlin/okhttp3/internal/connection/RoutePlanner.kt
index dff427f2359a..f61717ad573a 100644
--- a/okhttp/src/commonJvmAndroid/kotlin/okhttp3/internal/connection/RoutePlanner.kt
+++ b/okhttp/src/commonJvmAndroid/kotlin/okhttp3/internal/connection/RoutePlanner.kt
@@ -69,9 +69,9 @@ interface RoutePlanner {
   fun hasNext(failedConnection: RealConnection? = null): Boolean
 
   /**
-   * Returns true if the host and port are unchanged from when this was created. This is used to
-   * detect if followups need to do a full connection-finding process including DNS resolution, and
-   * certificate pin checks.
+   * Returns true if the host, port, and scheme are unchanged from when this was created. This is
+   * used to detect if followups need to do a full connection-finding process including DNS
+   * resolution, and certificate pin checks.
    */
   fun sameHostAndPort(url: HttpUrl): Boolean
 
diff --git a/okhttp/src/jvmTest/kotlin/okhttp3/CallTest.kt b/okhttp/src/jvmTest/kotlin/okhttp3/CallTest.kt
index e00c97a4e8e1..dd8487d1a3bf 100644
--- a/okhttp/src/jvmTest/kotlin/okhttp3/CallTest.kt
+++ b/okhttp/src/jvmTest/kotlin/okhttp3/CallTest.kt
@@ -97,6 +97,7 @@ import okhttp3.CallEvent.ResponseFailed
 import okhttp3.CallEvent.ResponseHeadersEnd
 import okhttp3.CallEvent.ResponseHeadersStart
 import okhttp3.CallEvent.RetryDecision
+import okhttp3.CallEvent.SecureConnectStart
 import okhttp3.CertificatePinner.Companion.pin
 import okhttp3.Credentials.basic
 import okhttp3.Headers.Companion.headersOf
@@ -2208,6 +2209,54 @@ open class CallTest {
     assertThat(server.takeRequest().exchangeIndex).isEqualTo(2)
   }
 
+  @Test
+  fun redirectFromHttpToHttpsOnSameHostAndPortDoesNotReusePlaintextConnection() {
+    val httpsUrl =
+      server
+        .url("/second")
+        .newBuilder()
+        .scheme("https")
+        .build()
+    server.enqueue(
+      MockResponse(
+        code = 301,
+        headers = headersOf("Location", httpsUrl.toString()),
+      ),
+    )
+    server.enqueue(MockResponse(body = "second-response"))
+
+    assertFailsWith<IOException> {
+      client.newCall(Request(url = server.url("/first"))).execute()
+    }
+
+    assertThat(server.takeRequest().requestLine).startsWith("GET /first HTTP/")
+    assertThat(eventRecorder.recordedEventTypes()).contains(SecureConnectStart::class)
+  }
+
+  @Test
+  fun redirectFromHttpsToHttpOnSameHostAndPortDoesNotReuseTlsConnection() {
+    enableTls()
+    val httpUrl =
+      server
+        .url("/second")
+        .newBuilder()
+        .scheme("http")
+        .build()
+    server.enqueue(
+      MockResponse(
+        code = 301,
+        headers = headersOf("Location", httpUrl.toString()),
+      ),
+    )
+    server.enqueue(MockResponse(body = "second-response"))
+
+    assertFailsWith<IOException> {
+      client.newCall(Request(url = server.url("/first"))).execute()
+    }
+
+    assertThat(server.takeRequest().requestLine).startsWith("GET /first HTTP/")
+  }
+
   @Test
   fun postRedirectsToGet() {
     server.enqueue(
diff --git a/okhttp/src/jvmTest/kotlin/okhttp3/FakeRoutePlanner.kt b/okhttp/src/jvmTest/kotlin/okhttp3/FakeRoutePlanner.kt
index f086e3d49f8b..fa382b7c0857 100644
--- a/okhttp/src/jvmTest/kotlin/okhttp3/FakeRoutePlanner.kt
+++ b/okhttp/src/jvmTest/kotlin/okhttp3/FakeRoutePlanner.kt
@@ -73,7 +73,8 @@ class FakeRoutePlanner(
   override fun hasNext(failedConnection: RealConnection?): Boolean =
     deferredPlans.isNotEmpty() || nextPlanIndex < plans.size || autoGeneratePlans
 
-  override fun sameHostAndPort(url: HttpUrl): Boolean = url.host == address.url.host && url.port == address.url.port
+  override fun sameHostAndPort(url: HttpUrl): Boolean =
+    url.host == address.url.host && url.port == address.url.port && url.scheme == address.url.scheme
 
   override fun close() {
     factory.close()