KDDI Mobile was a US mobile service set up by KDDI America for Japanese people living in the United States. It started on Sprint and later ran on AT&T. In January 2019, Telrite Holdings bought Locus Telecommunications, which ran KDDI Mobile and H2O Wireless. The KDDI Mobile brand is now defunct.
KDDI Mobile was acquired
KDDI America, the US arm of Japan’s KDDI, set up KDDI Mobile for Japanese expats. In January 2010, KDDI America bought Locus Telecommunications, which came to operate both the h2o Wireless and KDDI Mobile virtual carriers. In January 2019, Telrite Holdings bought Locus from KDDI America. Wikipedia now calls the KDDI Mobile carrier defunct. Its SIM website moved to h2owirelessjapan.com on February 28, 2019.
If you had a KDDI Mobile line
KDDI Mobile SIM customers were pointed to H2O Wireless Japan. A notice said kddimobilesim.com was moving to h2owirelessjapan.com on February 28, 2019, and asked customers to bookmark the new site. If your line stayed active after that move, start with H2O Wireless Japan for your account number and transfer PIN before porting to another carrier.
How KDDI Mobile ended
- April 9, 2007: MarketWatch reports KDDI will begin US mobile service on Sprint’s network.
- January 2010: KDDI America acquires Locus Telecommunications as a subsidiary.
- January 2019: Telrite Holdings acquires Locus Telecommunications, operator of h2o Wireless and KDDI Mobile, from KDDI America.
- February 28, 2019: The kddimobilesim.com site moves to h2owirelessjapan.com.
Why KDDI Mobile ended
KDDI America sold the business. In January 2019, Telrite Holdings bought Locus Telecommunications, the company that ran the h2o Wireless and KDDI Mobile virtual carriers. After the sale, the KDDI Mobile SIM site moved to H2O Wireless Japan, and Wikipedia lists the KDDI Mobile carrier as defunct. The sources do not state KDDI’s reasons for selling.
How to find who holds an old number now
- Check an old bill or payment record. It names the company that billed you last.
- Run the number through a carrier lookup tool. It shows the carrier that holds the number today.
- Call that carrier and ask for the account number and transfer PIN.
- Start the port from the new carrier. Never cancel the old line first.
Your right to keep a number
Number portability is federal law, not a carrier policy. The rule is the FCC’s: Portability: Keeping Your Phone Number When Changing Service Providers.
How we verified KDDI Mobile
BestCellular.com tracks active carriers and defunct ones. We keep both, because people still search for brands that no longer exist. Every fact on this page comes from the sources listed below, and we leave a detail out when no source states it. Where sources disagree, this page says so. If you can document a correction, tell us and we will check it against the sources.
Tracked and active are different counts on this site. KDDI Mobile counts in our tracked total, not in our active total, so it does not appear in tools built for live carriers.
Questions about KDDI Mobile
Is KDDI Mobile still available?
No. Wikipedia lists the KDDI Mobile virtual carrier as defunct. Its operator, Locus Telecommunications, was sold to Telrite Holdings in January 2019, and the KDDI Mobile SIM website moved to H2O Wireless Japan on February 28, 2019.
Which network did KDDI Mobile use?
AT&T at the end. KDDI Mobile began on Sprint’s network and later moved to AT&T, per Wikipedia. It was a virtual carrier that rented network capacity rather than running its own towers.
What happened to KDDI Mobile customers?
They were pointed to H2O Wireless Japan. A notice said kddimobilesim.com would move to h2owirelessjapan.com on February 28, 2019. H2O Wireless was the sister brand Locus also ran, and both went to Telrite Holdings.
Who was KDDI Mobile for?
Japanese people living in the United States. KDDI America set it up for that market, offered a Japanese-language handset, the KDDI Mobile 6600-J, and included calls to Japan in plan minutes, per Wikipedia.
Sources
Checked October 13, 2026.
- KDDI Mobile (Wikipedia): Purpose, Sprint then AT&T, Locus acquired Jan 2010, Telrite bought Locus Jan 2019, MVNO defunct, site moved Feb 28, 2019 (checked 2026-10-13).
- List of mobile virtual network operators in the United States (Wikipedia): Former-MVNO table: host AT&T (originally Sprint), GSM, end date January 2019 (checked 2026-10-13).
Best Cellular. “KDDI Mobile: What Happened,” BestCellular.com. https://bestcellular.com/kddi-mobile/
Free to reuse with credit. Licence, sources and the full dataset. All defunct carriers are listed on carriers that shut down.
Live carriers to look at instead
No carrier took over KDDI Mobile’s customers. These carriers publish their network and run today.