diff --git a/src/core/meshcop/dtls.hpp b/src/core/meshcop/dtls.hpp
index 8aebbc216..a3cc41411 100644
--- a/src/core/meshcop/dtls.hpp
+++ b/src/core/meshcop/dtls.hpp
@@ -351,7 +351,7 @@ private:
     {
         kGuardTimeNewConnectionMilli = 2000,
 #if !OPENTHREAD_CONFIG_COAP_SECURE_API_ENABLE
-        kApplicationDataMaxLength = 512,
+        kApplicationDataMaxLength = 1152,
 #else
         kApplicationDataMaxLength = OPENTHREAD_CONFIG_DTLS_APPLICATION_DATA_MAX_LENGTH,
 #endif