diff --git a/lib/libc/aarch64/string/Makefile.inc b/lib/libc/aarch64/string/Makefile.inc
--- a/lib/libc/aarch64/string/Makefile.inc
+++ b/lib/libc/aarch64/string/Makefile.inc
@@ -20,6 +20,10 @@
 	strnlen \
 	strrchr
 
+MDSRCS+= \
+        strlcpy.S \
+        strlcat.c
+
 #
 # Add the above functions. Generate an asm file that includes the needed
 # Arm Optimized Routines file defining the function name to the libc name.
diff --git a/lib/libc/aarch64/string/memchr.S b/lib/libc/aarch64/string/memchr.S
new file mode 100644
--- /dev/null
+++ b/lib/libc/aarch64/string/memchr.S
@@ -0,0 +1,4 @@
+	.weak memchr
+	.set memchr, __memchr_aarch64
+
+#include "aarch64/memchr.S"
diff --git a/lib/libc/aarch64/string/strlcat.c b/lib/libc/aarch64/string/strlcat.c
new file mode 100644
--- /dev/null
+++ b/lib/libc/aarch64/string/strlcat.c
@@ -0,0 +1,25 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2023 Robert Clausecker
+ */
+
+#include <sys/cdefs.h>
+
+#include <string.h>
+
+void *__memchr_aarch64(const void *, int, size_t);
+size_t __strlcpy(char *restrict, const char *restrict, size_t);
+
+size_t
+strlcat(char *restrict dst, const char *restrict src, size_t dstsize)
+{
+	char *loc = __memchr_aarch64(dst, '\0', dstsize);
+
+	if (loc != NULL) {
+		size_t dstlen = (size_t)(loc - dst);
+
+		return (dstlen + __strlcpy(loc, src, dstsize - dstlen));
+	} else
+		return (dstsize + strlen(src));
+}