diff --git a/tests/bluetooth/tester/overlay-bt_ll_sw_split.conf b/tests/bluetooth/tester/overlay-bt_ll_sw_split.conf
index df028ab0e0fc9..ac8366b95c0f0 100644
--- a/tests/bluetooth/tester/overlay-bt_ll_sw_split.conf
+++ b/tests/bluetooth/tester/overlay-bt_ll_sw_split.conf
@@ -67,3 +67,8 @@ CONFIG_BT_CTLR_ISO_TX_BUFFER_SIZE=259
 # Set advertising/scan data length to support large BAP BASEs
 CONFIG_BT_CTLR_ADV_DATA_LEN_MAX=191
 CONFIG_BT_CTLR_SCAN_DATA_LEN_MAX=191
+
+# ACL data sizes
+CONFIG_BT_BUF_ACL_TX_SIZE=251
+CONFIG_BT_BUF_ACL_RX_SIZE=255
+CONFIG_BT_CTLR_DATA_LENGTH_MAX=251