diff --git a/esphome/components/socket/socket.cpp b/esphome/components/socket/socket.cpp
index 54111892a0e..85197224810 100644
--- a/esphome/components/socket/socket.cpp
+++ b/esphome/components/socket/socket.cpp
@@ -8,13 +8,7 @@
 
 namespace esphome::socket {
 
-#ifdef USE_LWIP_FAST_SELECT
-// Shared ready() implementation for fd-based socket implementations (BSD and LWIP sockets).
-// Uses cached lwip_sock pointer for direct rcvevent read — no fd lookup overhead.
-bool socket_ready(struct lwip_sock *cached_sock, bool loop_monitored) {
-  return !loop_monitored || (cached_sock != nullptr && esphome_lwip_socket_has_data(cached_sock));
-}
-#elif defined(USE_SOCKET_SELECT_SUPPORT)
+#if defined(USE_SOCKET_SELECT_SUPPORT) && !defined(USE_LWIP_FAST_SELECT)
 // Shared ready() implementation for fd-based socket implementations (BSD and LWIP sockets).
 // Checks if the Application's select() loop has marked this fd as ready.
 bool socket_ready_fd(int fd, bool loop_monitored) { return !loop_monitored || App.is_socket_ready_(fd); }
diff --git a/esphome/components/socket/socket.h b/esphome/components/socket/socket.h
index 709d8066b13..8aec44a91f0 100644
--- a/esphome/components/socket/socket.h
+++ b/esphome/components/socket/socket.h
@@ -7,7 +7,7 @@
 #include "headers.h"
 
 #ifdef USE_LWIP_FAST_SELECT
-struct lwip_sock;
+#include "esphome/core/lwip_fast_select.h"
 #endif
 
 #if defined(USE_SOCKET_IMPL_LWIP_TCP) || defined(USE_SOCKET_IMPL_LWIP_SOCKETS) || defined(USE_SOCKET_IMPL_BSD_SOCKETS)
@@ -42,7 +42,9 @@ using ListenSocket = LWIPRawListenImpl;
 
 #ifdef USE_LWIP_FAST_SELECT
 /// Shared ready() helper using cached lwip_sock pointer for direct rcvevent read.
-bool socket_ready(struct lwip_sock *cached_sock, bool loop_monitored);
+inline bool socket_ready(struct lwip_sock *cached_sock, bool loop_monitored) {
+  return !loop_monitored || (cached_sock != nullptr && esphome_lwip_socket_has_data(cached_sock));
+}
 #elif defined(USE_SOCKET_SELECT_SUPPORT)
 /// Shared ready() helper for fd-based socket implementations.
 /// Checks if the Application's select() loop has marked this fd as ready.