diff --git a/examples/openthread/ot_ci_function.py b/examples/openthread/ot_ci_function.py
index 6c5ca2c6279..424381508b2 100644
--- a/examples/openthread/ot_ci_function.py
+++ b/examples/openthread/ot_ci_function.py
@@ -5,6 +5,7 @@
 import ipaddress
 import logging
 import os
+import random
 import re
 import socket
 import struct
@@ -259,11 +260,20 @@ def ot_ping(
     return tx_count, rx_count
 
 
-def ping_and_check(dut: IdfDut, target: str, tx_total: int = 10, timeout: int = 6, pass_rate: float = 0.8) -> None:
+def ping_and_check(
+    dut: IdfDut,
+    target: str,
+    tx_total: int = 10,
+    timeout: int = 6,
+    pass_rate: float = 0.8,
+    size: int = 10,
+    size_range: tuple[int, int] | None = None,
+) -> None:
     tx_count = 0
     rx_count = 0
     for _ in range(tx_total):
-        tx, rx = ot_ping(dut, target, timeout=timeout, count=1, size=10, interval=6)
+        ping_size = random.randint(*size_range) if size_range else size
+        tx, rx = ot_ping(dut, target, timeout=timeout, count=1, size=ping_size, interval=6)
         tx_count += tx
         rx_count += rx
 
diff --git a/examples/openthread/pytest_otbr.py b/examples/openthread/pytest_otbr.py
index c0429b97539..aec9c136aee 100644
--- a/examples/openthread/pytest_otbr.py
+++ b/examples/openthread/pytest_otbr.py
@@ -1158,9 +1158,9 @@ def test_ot_ssed_device(dut: tuple[IdfDut, IdfDut]) -> None:
         cli_rloc_addr = ':'.join(ocf.get_rloc_addr(leader).split(':')[:-1])
         ssed_address = f'{cli_rloc_addr}:{rloc16_decode_from_leader}'
 
-        ocf.ping_and_check(dut=leader, target=ssed_address, tx_total=10, timeout=6)
+        ocf.ping_and_check(dut=leader, target=ssed_address, tx_total=10, timeout=6, size_range=(10, 70))
         time.sleep(random.randint(5, 20))
-        ocf.ping_and_check(dut=leader, target=ssed_address, tx_total=10, timeout=6)
+        ocf.ping_and_check(dut=leader, target=ssed_address, tx_total=10, timeout=6, size_range=(100, 200))
     finally:
         ocf.execute_command(leader, 'factoryreset')
         ocf.hardreset_dut(ssed_device)