I keep finding conflicting information. I understand that a 090 prefix indicates a Japanese cell phone and when that's the case, there's no need to dial a city code. I've also seen that you remove the first 0 which would only be dialed from within Japan.

If this is true, I think I would dial 011-81-90 + the rest of the number.

Who can confirm?

i use 0118180 when calling from hi to tokyo. hope this helps.

Very helpful!

Thanks.

090 is a prefix for KDDI-au cell phone in Japan.
To call an au (pronounced ei-you) phone from US, dial 011 81 90 xxxx xxxx, so dropping the first zero from 090.
So you are correct!

011 81 90...will work. 090 is a prefix used for all cell phone companies, as is 080. Our Softbank phones are all 090 prefixes, and my daughters old AU phone was 080 prefix. Years ago, certain prefixes belonged to certain companies, but that is no longer true. You can now keep your cell phone number the same even if you change providers, which was not true in the past when the prefix was company specific.

Thanks everybody!