diff --git a/src/async_port/async_can.cpp b/src/async_port/async_can.cpp
index e88cab5..7343ee3 100644
--- a/src/async_port/async_can.cpp
+++ b/src/async_port/async_can.cpp
@@ -76,15 +76,15 @@ bool AsyncCAN::SetupPort() {
 }
 
 void AsyncCAN::StopService() {
-  // release port fd
-  const int close_result = ::close(can_fd_);
-  can_fd_ = -1;
-
   // stop io thread
   io_context_.stop();
   if (io_thread_.joinable()) io_thread_.join();
   io_context_.reset();
 
+  // release port fd
+  const int close_result = ::close(can_fd_);
+  can_fd_ = -1;
+
   port_opened_ = false;
 }
 
diff --git a/src/async_port/async_serial.cpp b/src/async_port/async_serial.cpp
index fcd561d..bc1595a 100644
--- a/src/async_port/async_serial.cpp
+++ b/src/async_port/async_serial.cpp
@@ -71,16 +71,16 @@ bool AsyncSerial::SetupPort() {
 }
 
 void AsyncSerial::StopService() {
-  if (IsOpened()) {
-    serial_port_.cancel();
-    serial_port_.close();
-  }
-
   // stop io thread
   io_context_.stop();
   if (io_thread_.joinable()) io_thread_.join();
   io_context_.reset();
 
+  if (IsOpened()) {
+    serial_port_.cancel();
+    serial_port_.close();
+  }
+
   port_opened_ = false;
 }