diff --git a/features/cellular/framework/API/CellularNetwork.h b/features/cellular/framework/API/CellularNetwork.h
index 4094a07838..0b9fc19e5e 100644
--- a/features/cellular/framework/API/CellularNetwork.h
+++ b/features/cellular/framework/API/CellularNetwork.h
@@ -272,9 +272,11 @@ public:
 
     /** Request attach to network.
      *
+     *  @deprecated Parameter timeout will be deprecated. Use mbed-os/features/cellular/framework/API/CellularDevice.h set_timeout instead.
      *  @param timeout milliseconds to wait for attach response
      *  @return        zero on success
      */
+    MBED_DEPRECATED_SINCE("mbed-os-5.9", "Parameter timeout will be deprecated. Use mbed-os/features/cellular/framework/API/CellularDevice.h set_timeout instead.")
     virtual nsapi_error_t set_attach(int timeout = 10*1000) = 0;
 
     /** Request attach status from network.