diff --git a/tests/subsys/lorawan/frag_decoder/testcase.yaml b/tests/subsys/lorawan/frag_decoder/testcase.yaml
index 7182fd3cfe6..d5ea2f8d714 100644
--- a/tests/subsys/lorawan/frag_decoder/testcase.yaml
+++ b/tests/subsys/lorawan/frag_decoder/testcase.yaml
@@ -7,6 +7,7 @@ tests:
       - native_sim
     extra_configs:
       - CONFIG_LORAWAN_FRAG_TRANSPORT_DECODER_SEMTECH=y
+      - CONFIG_NATIVE_EXTRA_CMDLINE_ARGS="seed=1"
   lorawan.frag_decoder.lowmem.high_redundancy:
     platform_allow:
       - native_sim
@@ -19,3 +20,4 @@ tests:
     extra_configs:
       - CONFIG_LORAWAN_FRAG_TRANSPORT_DECODER_LOWMEM=y
       - CONFIG_LORAWAN_FRAG_TRANSPORT_MAX_REDUNDANCY=10
+      - CONFIG_NATIVE_EXTRA_CMDLINE_ARGS="seed=1"