diff --git a/src/quic_conn.c b/src/quic_conn.c
index 3de0d9005..290df7179 100644
--- a/src/quic_conn.c
+++ b/src/quic_conn.c
@@ -6585,16 +6585,16 @@ static inline void quic_rx_pkts_del(struct quic_conn *qc)
 
 	list_for_each_entry_safe(pkt, pktback, &qc->rx.pkt_list, qc_rx_pkt_list) {
 		TRACE_PRINTF(TRACE_LEVEL_DEVELOPER, QUIC_EV_CONN_LPKT, qc, 0, 0, 0,
-		             "pkt #%lld(type=%d,len=%zu,rawlen=%zu,refcnt=%u) (diff: %zd)",
+		             "pkt #%lld(type=%d,len=%llu,rawlen=%llu,refcnt=%u) (diff: %zd)",
 		             (long long)pkt->pn_node.key,
-		             pkt->type, pkt->len, pkt->raw_len, pkt->refcnt,
+		             pkt->type, (ull)pkt->len, (ull)pkt->raw_len, pkt->refcnt,
 		             (unsigned char *)b_head(&qc->rx.buf) - pkt->data);
 		if (pkt->data != (unsigned char *)b_head(&qc->rx.buf)) {
 			size_t cdata;
 
 			cdata = b_contig_data(&qc->rx.buf, 0);
 			TRACE_PRINTF(TRACE_LEVEL_DEVELOPER, QUIC_EV_CONN_LPKT, qc, 0, 0, 0,
-			             "cdata=%zu *b_head()=0x%x", cdata, *b_head(&qc->rx.buf));
+			             "cdata=%llu *b_head()=0x%x", (ull)cdata, *b_head(&qc->rx.buf));
 			if (cdata && !*b_head(&qc->rx.buf)) {
 				/* Consume the remaining data */
 				b_del(&qc->rx.buf, cdata);
@@ -6662,7 +6662,7 @@ static void qc_rx_pkt_handle(struct quic_conn *qc, struct quic_rx_packet *pkt,
 	b_cspace = b_contig_space(&qc->rx.buf);
 	if (b_cspace < pkt->len) {
 		TRACE_PRINTF(TRACE_LEVEL_DEVELOPER, QUIC_EV_CONN_LPKT, qc, 0, 0, 0,
-		             "bspace=%zu pkt->len=%zu", b_cspace, pkt->len);
+		             "bspace=%llu pkt->len=%llu", (ull)b_cspace, (ull)pkt->len);
 		/* Do not consume buf if space not at the end. */
 		if (b_tail(&qc->rx.buf) + b_cspace < b_wrap(&qc->rx.buf)) {
 			TRACE_PROTO("Packet dropped",