Wikipedia:IPA for Japanese

Consonants
IPA	Japanese example	English approximation
b	basho	bog
ç	hito	hero
ɕ	shita, shugo	show
d	dōmo	dome
dz, z^[1]	zazen	zen, rods
dʑ, ʑ^[1]	jibun, gojuu	gelatin, fusion
ɸ	fugu	food (lips don't touch teeth, more like blowing out a candle)
ɡ	gakusei	gape
h	hon	hone
j	yakusha, kyū	yak
k	kuru	skate
m	mikan	much
n	nattō	not
ɴ	nihon	long
ŋ	ringo	finger
p	pan	span
ɽ^[2]	roku	close to /t/ in auto in American English, or between lock and Scottish rock ([l] and [ɾ]).
s	suru	sue
t	taberu	tan
ts	tsunami	cats
tɕ	chikai, kinchō	itch
w͍^[3]	wasabi	was
ʔ	(in Ryukyu languages)	oh-oh!

Suprasegmentals
IPA	Japanese examples	English examples
ː	long vowel: ojiisan	re-equalize
ː	double consonant: seppuku	big gram (compare big ram)
ꜜ	tone drops: kaꜜki (oyster), kakiꜜ (fence)^[6]

Notes

1 2 The fricative [z]~[ʑ] is in free variation with the affricate [dz]~[dʑ]. Usually, this is represented phonemically as /z/.
↑ The Japanese r varies between a postalveolar flap [ɽ] and an alveolar lateral flap [ɺ].
↑ The Japanese w is not equivalent to a typical IPA [w] since it is pronounced with lip compression rather than rounding. The labial spreading diacritic is an extended IPA character.
↑ The Japanese /e/ doesn't quite line up with any English vowel, though the nearest equivalents are the vowel of pay (for most English dialects) and the vowel of met; the Japanese vowel is usually articulated at a point between the two.
1 2 There is no simple symbol in the IPA for Japanese u, which is neither rounded [u] nor unrounded [ɯ], but compressed [ɯ͡β̞]. The labial spreading diacritic is an extended IPA character.
↑ The position of this downstep, which does not occur in all words, varies between dialects, and frequently is not indicated. The downstep is a drop in pitch; the word rises in pitch before the ꜜ. When ꜜ occurs after the final syllable of a word, any attached grammatical particles will have low tone.