The au version of the iPhone was "American AT & T only" SIM lock free by Atsushi Ishikawa --Weekly ASCII

When traveling abroad, international roaming on smartphones is convenient, but the flat-rate packet system is generally 2980 yen a day, which gives a pretty high impression to use for several days. If you want to make it cheaper, it is wise to rent a local Wi-Fi router in Japan.

However, although that is enough for the general public, it is still fun to buy and use a SIM card of a local carrier as a "smartphone lover". Sometimes buying a SIM card is a more memorable trip than sightseeing or souvenirs.

On a business trip to the United States in May, I was planning to get an AT & T prepaid SIM card, insert it into my iPhone 6, and use it. When I arrived at the hotel, I inserted the AT & T prepaid SIM card into my iPhone 6 and noticed it when I finished activating it. "Oh, this is not the SIM-free version of the iPhone 6, but the iPhone 6 purchased from au."

The author owns three iPhones, the iPhone 6 (silver) contracted with au, the SIM-free version iPhone 6 (gold), and the iPhone 6 (space gray) contracted with Verizon in the United States. Originally, I had to insert the AT & T SIM card into the SIM-free iPhone 6, but what went wrong was that I inserted the AT & T SIM card into the au iPhone 6. However, looking at the antenna pictogram, it is written as AT & T, communication is also connected, and LTE can be used normally. The speed is relatively fast and the area feels satisfying.

I also tried inserting a Verizon, T-Mobile, or Softbank SIM card into an au iPhone 6, but I couldn't use it. Apparently, only AT & T's SIM card will be unlocked in the United States. When I checked with KDDI's public relations, I received a comment saying, "We are not informing you, and we do not guarantee the operation." However, I did not deny that the au iPhone can be used with AT & T's SIM card, creating an atmosphere that seems to be no problem even if it is used. In other words, the au version of the iPhone can be used only with AT & T in the United States without SIM lock.

By the way, if you buy a SIM card at AT & T, the SIM card fee is $ 9.99, 1GB of data capacity is $ 45 per month, and 2.5GB is $ 60 per month.

For the average user, buying a SIM card on a limited time trip to the United States can be a hassle and time consuming process, so many people would like to avoid it if possible. AT & T SIM cards can also be purchased at vending machines at San Francisco Airport, but they are actually only near the boarding gate and can only be purchased on the way home. If possible, it is encouraging to be able to procure a SIM card before going to the United States.

When I was looking for ways to buy an American SIM card in Japan in advance, it turned out that the au online shop sells an MVNO SIM card called "H2O Wireless" that uses the AT & T network. H2O Wireless is a subsidiary of KDDI, and it seems that it started selling on its own site before the SIM unlock obligation from May.

I tried using the H2O Wireless SIM card by inserting it into the au iPhone 6 when I went to the United States in June. There are some troublesome points such as having to download the setting profile in a Wi-Fi environment when activating, but since it is a subsidiary of KDDI, you can set it while looking at the Japanese manual, so that's about it. Is encouraging. Like AT & T, the H2O Wireless SIM card could be used without any problems.

If you buy a SIM card in Japan, it costs 3780 yen, but you can get it for $ 9.99 at home electronics retail stores in the United States. Whether to prepare in Japan in advance or buy in the United States will be quite annoying. By the way, the price plan is $ 30, and you can use 500MB of data capacity for 30 days. If you pay $ 60, you'll have unlimited data capacity, but it doesn't support tethering.

An au iPhone that allows you to use a local SIM card in the United States without having to wait for the iPhone to be released this fall. However, when I actually use it, I remove the au SIM card and insert the local SIM card, so I cannot receive calls to au phone numbers.

Moreover, in the case of au, it is not possible to transfer to an overseas number, so it is not possible to transfer to an AT & T or H2O Wireless number. After a lot of research, I found that AT & T's SIM card could be used with au's iPhone 4S, so while inserting the local SIM card into the iPhone I was using before, I used the iPhone I'm currently using for roaming to receive incoming calls, or It will be necessary to devise a method such as transferring to an IP phone application that issues a number such as 050.

■ Related sites iPhone (au) au Online Shop (H2O Wireless Nano SIM Starter Kit) H2O Wireless