diff --git a/CMake/switch/asio/include/errno.h b/CMake/switch/asio/include/errno.h
new file mode 100644
index 000000000..209a0eae1
--- /dev/null
+++ b/CMake/switch/asio/include/errno.h
@@ -0,0 +1,5 @@
+#pragma once
+
+#include_next <errno.h>
+
+#define ESHUTDOWN (__ELASTERROR + 1)
diff --git a/CMake/switch/asio/include/net/if.h b/CMake/switch/asio/include/net/if.h
new file mode 100644
index 000000000..d2fa1021f
--- /dev/null
+++ b/CMake/switch/asio/include/net/if.h
@@ -0,0 +1,24 @@
+#ifndef _NET_IF_H
+#define _NET_IF_H 1
+
+#define IF_NAMESIZE 16
+
+struct if_nameindex {
+  unsigned int if_index;
+  char *if_name;
+};
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+unsigned int if_nametoindex(const char *__ifname);
+char *if_indextoname(unsigned int __ifindex, char *__ifname);
+struct if_nameindex *if_nameindex();
+void if_freenameindex(struct if_nameindex *__ptr);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/CMake/switch/asio/include/netinet/in.h b/CMake/switch/asio/include/netinet/in.h
new file mode 100644
index 000000000..4b1a8f919
--- /dev/null
+++ b/CMake/switch/asio/include/netinet/in.h
@@ -0,0 +1,8 @@
+#pragma once
+
+#include_next <netinet/in.h>
+
+struct ipv6_mreq {
+  struct in6_addr ipv6mr_multiaddr;
+  unsigned ipv6mr_interface;
+};
diff --git a/CMake/switch/asio/include/sys/uio.h b/CMake/switch/asio/include/sys/uio.h
new file mode 100644
index 000000000..4c3761916
--- /dev/null
+++ b/CMake/switch/asio/include/sys/uio.h
@@ -0,0 +1,10 @@
+#ifndef _SYS_UIO_H
+#define _SYS_UIO_H 1
+
+#include <sys/types.h>
+#include <sys/_iovec.h>
+
+ssize_t readv(int __fd, const struct iovec *__iovec, int __count);
+ssize_t writev(int __fd, const struct iovec *__iovec, int __count);
+
+#endif
diff --git a/CMake/switch/asio/include/sys/un.h b/CMake/switch/asio/include/sys/un.h
new file mode 100644
index 000000000..12a786d8c
--- /dev/null
+++ b/CMake/switch/asio/include/sys/un.h
@@ -0,0 +1,16 @@
+#ifndef _SYS_UN_H
+#define _SYS_UN_H 1
+
+#include <sys/types.h>
+
+#ifndef _SA_FAMILY_T_DECLARED
+typedef __sa_family_t sa_family_t;
+#define	_SA_FAMILY_T_DECLARED
+#endif
+
+struct sockaddr_un {
+  sa_family_t sun_family;
+  char sun_path[108];
+};
+
+#endif
diff --git a/CMake/switch/asio_defs.cmake b/CMake/switch/asio_defs.cmake
new file mode 100644
index 000000000..50451a2d2
--- /dev/null
+++ b/CMake/switch/asio_defs.cmake
@@ -0,0 +1,5 @@
+# Enables a number of header file definitions required by ASIO
+target_compile_definitions(asio INTERFACE _DEFAULT_SOURCE=ON)
+
+# Missing headers and declarations provided by DevilutionX
+target_include_directories(asio BEFORE INTERFACE CMake/switch/asio/include)
diff --git a/CMake/switch_defs.cmake b/CMake/switch/switch_defs.cmake
similarity index 100%
rename from CMake/switch_defs.cmake
rename to CMake/switch/switch_defs.cmake
diff --git a/CMakeLists.txt b/CMakeLists.txt
index a7b67c2da..9cd6ad636 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -132,6 +132,7 @@ if(GPERF)
 endif()
 
 if(NINTENDO_SWITCH)
+  list(APPEND CMAKE_MODULE_PATH "${DevilutionX_SOURCE_DIR}/CMake/switch")
   include(switch_defs)
 endif()
 
@@ -268,6 +269,8 @@ if(NOT NONET AND NOT DISABLE_TCP)
         ASIO_HAS_UNISTD_H=ON)
 
       target_include_directories(asio BEFORE INTERFACE CMake/ctr/asio/include)
+  elseif(NINTENDO_SWITCH)
+    include(asio_defs)
   endif()
 endif()