diff --git a/lib/libc/locale/Makefile.inc b/lib/libc/locale/Makefile.inc
index ffef22862e8f..c2f2f4e61727 100644
--- a/lib/libc/locale/Makefile.inc
+++ b/lib/libc/locale/Makefile.inc
@@ -4,11 +4,11 @@
 # locale sources
 .PATH: ${.CURDIR}/${LIBC_ARCH}/locale ${.CURDIR}/locale
 
-SRCS+=	ascii.c big5.c btowc.c c16rtomb.c c32rtomb.c collate.c collcmp.c euc.c \
-	fix_grouping.c gb18030.c gb2312.c gbk.c ctype.c isctype.c iswctype.c \
+SRCS+=	ascii.c big5.c btowc.c collate.c collcmp.c euc.c fix_grouping.c \
+	gb18030.c gb2312.c gbk.c ctype.c isctype.c iswctype.c \
 	ldpart.c lmessages.c lmonetary.c lnumeric.c localeconv.c mblen.c \
 	mbrlen.c \
-	mbrtoc16.c mbrtoc32.c mbrtowc.c mbsinit.c mbsnrtowcs.c \
+	mbrtowc.c mbsinit.c mbsnrtowcs.c \
 	mbsrtowcs.c mbtowc.c mbstowcs.c \
 	mskanji.c nextwctype.c nl_langinfo.c nomacros.c none.c rpmatch.c \
 	rune.c \
@@ -23,6 +23,12 @@ SRCS+=	ascii.c big5.c btowc.c c16rtomb.c c32rtomb.c collate.c collcmp.c euc.c \
 	wcwidth.c\
 	xlocale.c
 
+.if ${MK_ICONV} != "no"
+SRCS+=	c16rtomb_iconv.c c32rtomb_iconv.c mbrtoc16_iconv.c mbrtoc32_iconv.c
+.else
+SRCS+=	c16rtomb.c c32rtomb.c mbrtoc16.c mbrtoc32.c
+.endif
+
 SYM_MAPS+=${.CURDIR}/locale/Symbol.map
 
 MAN+=	btowc.3 \
diff --git a/lib/libc/locale/c16rtomb_iconv.c b/lib/libc/locale/c16rtomb_iconv.c
new file mode 100644
index 000000000000..86bd9dab2a52
--- /dev/null
+++ b/lib/libc/locale/c16rtomb_iconv.c
@@ -0,0 +1,8 @@
+/* $FreeBSD$ */
+#define	charXX_t	char16_t
+#define	cXXrtomb	c16rtomb
+#define	cXXrtomb_l	c16rtomb_l
+#define	SRCBUF_LEN	2
+#define	UTF_XX_INTERNAL	"UTF-16-INTERNAL"
+
+#include "cXXrtomb_iconv.h"
diff --git a/lib/libc/locale/c32rtomb_iconv.c b/lib/libc/locale/c32rtomb_iconv.c
new file mode 100644
index 000000000000..dabbfd7f7ab4
--- /dev/null
+++ b/lib/libc/locale/c32rtomb_iconv.c
@@ -0,0 +1,8 @@
+/* $FreeBSD$ */
+#define	charXX_t	char32_t
+#define	cXXrtomb	c32rtomb
+#define	cXXrtomb_l	c32rtomb_l
+#define	SRCBUF_LEN	1
+#define	UTF_XX_INTERNAL	"UTF-32-INTERNAL"
+
+#include "cXXrtomb_iconv.h"
diff --git a/lib/libc/locale/cXXrtomb_iconv.h b/lib/libc/locale/cXXrtomb_iconv.h
new file mode 100644
index 000000000000..d6e7ce0ae3ac
--- /dev/null
+++ b/lib/libc/locale/cXXrtomb_iconv.h
@@ -0,0 +1,115 @@
+/*-
+ * Copyright (c) 2013 Ed Schouten <ed@FreeBSD.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/queue.h>
+
+#include <assert.h>
+#include <errno.h>
+#include <langinfo.h>
+#include <uchar.h>
+
+#include "../iconv/citrus_hash.h"
+#include "../iconv/citrus_module.h"
+#include "../iconv/citrus_iconv.h"
+#include "xlocale_private.h"
+
+typedef struct {
+	bool			initialized;
+	struct _citrus_iconv	iconv;
+	union {
+		charXX_t	widechar[SRCBUF_LEN];
+		char		bytes[sizeof(charXX_t) * SRCBUF_LEN];
+	} srcbuf;
+	size_t			srcbuf_len;
+} _ConversionState;
+_Static_assert(sizeof(_ConversionState) <= sizeof(mbstate_t),
+    "Size of _ConversionState must not exceed mbstate_t's size.");
+
+size_t
+cXXrtomb_l(char * __restrict s, charXX_t c, mbstate_t * __restrict ps,
+    locale_t locale)
+{
+	_ConversionState *cs;
+	struct _citrus_iconv *handle;
+	char *src, *dst;
+	size_t srcleft, dstleft, invlen;
+	int err;
+
+	FIX_LOCALE(locale);
+	if (ps == NULL)
+		ps = &locale->cXXrtomb;
+	cs = (_ConversionState *)ps;
+	handle = &cs->iconv;
+
+	/* Reinitialize mbstate_t. */
+	if (s == NULL || !cs->initialized) {
+		if (_citrus_iconv_open(&handle, UTF_XX_INTERNAL,
+		    nl_langinfo_l(CODESET, locale)) != 0) {
+			cs->initialized = false;
+			errno = EINVAL;
+			return (-1);
+		}
+		handle->cv_shared->ci_discard_ilseq = true;
+		handle->cv_shared->ci_hooks = NULL;
+		cs->srcbuf_len = 0;
+		cs->initialized = true;
+		if (s == NULL)
+			return (1);
+	}
+
+	assert(cs->srcbuf_len < sizeof(cs->srcbuf.widechar) / sizeof(charXX_t));
+	cs->srcbuf.widechar[cs->srcbuf_len++] = c;
+
+	/* Perform conversion. */
+	src = cs->srcbuf.bytes;
+	srcleft = cs->srcbuf_len * sizeof(charXX_t);
+	dst = s;
+	dstleft = MB_CUR_MAX_L(locale);
+	err = _citrus_iconv_convert(handle, &src, &srcleft, &dst, &dstleft,
+	    0, &invlen);
+
+	/* Character is part of a surrogate pair. We need more input. */
+	if (err == EINVAL)
+		return (0);
+	cs->srcbuf_len = 0;
+	
+	/* Illegal sequence. */
+	if (dst == s) {
+		errno = EILSEQ;
+		return ((size_t)-1);
+	}
+	return (dst - s);
+}
+
+size_t
+cXXrtomb(char * __restrict s, charXX_t c, mbstate_t * __restrict ps)
+{
+
+	return (cXXrtomb_l(s, c, ps, __get_locale()));
+}
diff --git a/lib/libc/locale/mbrtoc16_iconv.c b/lib/libc/locale/mbrtoc16_iconv.c
new file mode 100644
index 000000000000..f1eaf1925496
--- /dev/null
+++ b/lib/libc/locale/mbrtoc16_iconv.c
@@ -0,0 +1,8 @@
+/* $FreeBSD$ */
+#define	charXX_t	char16_t
+#define	mbrtocXX	mbrtoc16
+#define	mbrtocXX_l	mbrtoc16_l
+#define	DSTBUF_LEN	2
+#define	UTF_XX_INTERNAL	"UTF-16-INTERNAL"
+
+#include "mbrtocXX_iconv.h"
diff --git a/lib/libc/locale/mbrtoc32_iconv.c b/lib/libc/locale/mbrtoc32_iconv.c
new file mode 100644
index 000000000000..ec2c0145d9d6
--- /dev/null
+++ b/lib/libc/locale/mbrtoc32_iconv.c
@@ -0,0 +1,8 @@
+/* $FreeBSD$ */
+#define	charXX_t	char32_t
+#define	mbrtocXX	mbrtoc32
+#define	mbrtocXX_l	mbrtoc32_l
+#define	DSTBUF_LEN	1
+#define	UTF_XX_INTERNAL	"UTF-32-INTERNAL"
+
+#include "mbrtocXX_iconv.h"
diff --git a/lib/libc/locale/mbrtocXX_iconv.h b/lib/libc/locale/mbrtocXX_iconv.h
new file mode 100644
index 000000000000..9eb6f6831eb6
--- /dev/null
+++ b/lib/libc/locale/mbrtocXX_iconv.h
@@ -0,0 +1,158 @@
+/*-
+ * Copyright (c) 2013 Ed Schouten <ed@FreeBSD.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/queue.h>
+
+#include <assert.h>
+#include <errno.h>
+#include <langinfo.h>
+#include <limits.h>
+#include <string.h>
+#include <uchar.h>
+
+#include "../iconv/citrus_hash.h"
+#include "../iconv/citrus_module.h"
+#include "../iconv/citrus_iconv.h"
+#include "xlocale_private.h"
+
+typedef struct {
+	bool			initialized;
+	struct _citrus_iconv	iconv;
+	char			srcbuf[MB_LEN_MAX];
+	size_t			srcbuf_len;
+	union {
+		charXX_t	widechar[DSTBUF_LEN];
+		char		bytes[sizeof(charXX_t) * DSTBUF_LEN];
+	} dstbuf;
+	size_t			dstbuf_len;
+} _ConversionState;
+_Static_assert(sizeof(_ConversionState) <= sizeof(mbstate_t),
+    "Size of _ConversionState must not exceed mbstate_t's size.");
+
+size_t
+mbrtocXX_l(charXX_t * __restrict pc, const char * __restrict s, size_t n,
+    mbstate_t * __restrict ps, locale_t locale)
+{
+	_ConversionState *cs;
+	struct _citrus_iconv *handle;
+	size_t i, retval;
+	charXX_t retchar;
+
+	FIX_LOCALE(locale);
+	if (ps == NULL)
+		ps = &locale->mbrtocXX;
+	cs = (_ConversionState *)ps;
+	handle = &cs->iconv;
+
+	/* Reinitialize mbstate_t. */
+	if (s == NULL || !cs->initialized) {
+		if (_citrus_iconv_open(&handle,
+		    nl_langinfo_l(CODESET, locale), UTF_XX_INTERNAL) != 0) {
+			cs->initialized = false;
+			errno = EINVAL;
+			return (-1);
+		}
+		handle->cv_shared->ci_discard_ilseq = true;
+		handle->cv_shared->ci_hooks = NULL;
+		cs->srcbuf_len = cs->dstbuf_len = 0;
+		cs->initialized = true;
+		if (s == NULL)
+			return (0);
+	}
+
+	/* See if we still have characters left from the previous invocation. */
+	if (cs->dstbuf_len > 0) {
+		retval = (size_t)-3;
+		goto return_char;
+	}
+
+	/* Fill up the read buffer as far as possible. */
+	if (n > sizeof(cs->srcbuf) - cs->srcbuf_len)
+		n = sizeof(cs->srcbuf) - cs->srcbuf_len;
+	memcpy(cs->srcbuf + cs->srcbuf_len, s, n);
+
+	/* Convert as few characters to the dst buffer as possible. */
+	for (i = 0; ; i++) {
+		char *src, *dst;
+		size_t srcleft, dstleft, invlen;
+		int err;
+
+		src = cs->srcbuf;
+		srcleft = cs->srcbuf_len + n;
+		dst = cs->dstbuf.bytes;
+		dstleft = i * sizeof(charXX_t);
+		assert(srcleft <= sizeof(cs->srcbuf) &&
+		    dstleft <= sizeof(cs->dstbuf.bytes));
+		err = _citrus_iconv_convert(handle, &src, &srcleft,
+		    &dst, &dstleft, 0, &invlen);
+		cs->dstbuf_len = (dst - cs->dstbuf.bytes) / sizeof(charXX_t);
+
+		/* Got new character(s). Return the first. */
+		if (cs->dstbuf_len > 0) {
+			assert(src - cs->srcbuf > cs->srcbuf_len);
+			retval = src - cs->srcbuf - cs->srcbuf_len;
+			cs->srcbuf_len = 0;
+			goto return_char;
+		}
+
+		/* Increase dst buffer size, to obtain the surrogate pair. */
+		if (err == E2BIG)
+			continue;
+
+		/* Illegal sequence. */
+		if (invlen > 0) {
+			cs->srcbuf_len = 0;
+			errno = EILSEQ;
+			return ((size_t)-1);
+		}
+
+		/* Save unprocessed remainder for the next invocation. */
+		memmove(cs->srcbuf, src, srcleft);
+		cs->srcbuf_len = srcleft;
+		return ((size_t)-2);
+	}
+
+return_char:
+	retchar = cs->dstbuf.widechar[0];
+	memmove(&cs->dstbuf.widechar[0], &cs->dstbuf.widechar[1],
+	    --cs->dstbuf_len * sizeof(charXX_t));
+	if (pc != NULL)
+		*pc = retchar;
+	if (retchar == 0)
+		return (0);
+	return (retval);
+}
+
+size_t
+mbrtocXX(charXX_t * __restrict pc, const char * __restrict s, size_t n,
+    mbstate_t * __restrict ps)
+{
+
+	return (mbrtocXX_l(pc, s, n, ps, __get_locale()));
+}
diff --git a/tools/regression/lib/libc/locale/test-c16rtomb.c b/tools/regression/lib/libc/locale/test-c16rtomb.c
index eb889468e8c4..2c188fa337b8 100644
--- a/tools/regression/lib/libc/locale/test-c16rtomb.c
+++ b/tools/regression/lib/libc/locale/test-c16rtomb.c
@@ -82,6 +82,34 @@ main(int argc, char *argv[])
 	assert(c16rtomb(buf, 0xd83d, &s) == 0);
 	assert(c16rtomb(buf, 0xdca9, &s) == (size_t)-1);
 	assert(errno == EILSEQ);
+	assert((unsigned char)buf[0] == 0xcc);
+
+	/*
+	 * ISO8859-1.
+	 */
+
+	assert(strcmp(setlocale(LC_CTYPE, "en_US.ISO8859-1"),
+	    "en_US.ISO8859-1") == 0);
+
+	/* Unicode character 'Euro sign'. */
+	memset(&s, 0, sizeof(s));
+	memset(buf, 0xcc, sizeof(buf));
+	assert(c16rtomb(buf, 0x20ac, &s) == (size_t)-1);
+	assert(errno == EILSEQ);
+	assert((unsigned char)buf[0] == 0xcc);
+
+	/*
+	 * ISO8859-15.
+	 */
+
+	assert(strcmp(setlocale(LC_CTYPE, "en_US.ISO8859-15"),
+	    "en_US.ISO8859-15") == 0);
+
+	/* Unicode character 'Euro sign'. */
+	memset(&s, 0, sizeof(s));
+	memset(buf, 0xcc, sizeof(buf));
+	assert(c16rtomb(buf, 0x20ac, &s) == 1);
+	assert((unsigned char)buf[0] == 0xa4 && (unsigned char)buf[1] == 0xcc);
 
 	/*
 	 * UTF-8.
@@ -104,12 +132,14 @@ main(int argc, char *argv[])
 	assert(c16rtomb(buf, 0xd83d, &s) == 0);
 	assert(c16rtomb(buf, L'A', &s) == (size_t)-1);
 	assert(errno == EILSEQ);
+	assert((unsigned char)buf[0] == 0xcc);
 
 	/* Invalid code; 'Pile of poo' without the lead surrogate. */
 	memset(&s, 0, sizeof(s));
 	memset(buf, 0xcc, sizeof(buf));
 	assert(c16rtomb(buf, 0xdca9, &s) == (size_t)-1);
 	assert(errno == EILSEQ);
+	assert((unsigned char)buf[0] == 0xcc);
 
 	printf("ok 1 - c16rtomb()\n");
 }
diff --git a/tools/regression/lib/libc/locale/test-mbrtoc16.c b/tools/regression/lib/libc/locale/test-mbrtoc16.c
index 88e8091d43ac..f709a9c80323 100644
--- a/tools/regression/lib/libc/locale/test-mbrtoc16.c
+++ b/tools/regression/lib/libc/locale/test-mbrtoc16.c
@@ -85,6 +85,37 @@ main(int argc, char *argv[])
 	assert(mbrtoc16(&c16, "", 0, &s) == (size_t)-2);
 	assert(c16 == L'z');
 
+	/* Check that mbrtoc16() doesn't read ahead too aggressively. */
+	memset(&s, 0, sizeof(s));
+	assert(mbrtoc16(&c16, "AB", 2, &s) == 1);
+	assert(c16 == L'A');
+	assert(mbrtoc16(&c16, "C", 1, &s) == 1);
+	assert(c16 == L'C');
+
+	/*
+	 * ISO-8859-1.
+	 */
+
+	assert(strcmp(setlocale(LC_CTYPE, "en_US.ISO8859-1"),
+	    "en_US.ISO8859-1") == 0);
+
+	/* Currency sign. */
+	memset(&s, 0, sizeof(s));
+	assert(mbrtoc16(&c16, "\xa4", 1, &s) == 1);
+	assert(c16 == 0xa4);
+
+	/*
+	 * ISO-8859-15.
+	 */
+
+	assert(strcmp(setlocale(LC_CTYPE, "en_US.ISO8859-15"),
+	    "en_US.ISO8859-15") == 0);
+
+	/* Euro sign. */
+	memset(&s, 0, sizeof(s));
+	assert(mbrtoc16(&c16, "\xa4", 1, &s) == 1);
+	assert(c16 == 0x20ac);
+
 	/*
 	 * UTF-8.
 	 */
@@ -144,6 +175,20 @@ main(int argc, char *argv[])
 	assert(mbrtoc16(&c16, "", 0, &s) == (size_t)-3);
 	assert(c16 == 0xdca9);
 
+	/* Letter e with acute, precomposed. */
+	memset(&s, 0, sizeof(s));
+	c16 = 0;
+	assert(mbrtoc16(&c16, "\xc3\xa9", 2, &s) == 2);
+	assert(c16 == 0xe9);
+
+	/* Letter e with acute, combined. */
+	memset(&s, 0, sizeof(s));
+	c16 = 0;
+	assert(mbrtoc16(&c16, "\x65\xcc\x81", 3, &s) == 1);
+	assert(c16 == 0x65);
+	assert(mbrtoc16(&c16, "\xcc\x81", 2, &s) == 2);
+	assert(c16 == 0x301);
+
 	printf("ok 1 - mbrtoc16()\n");
 
 	return (0);