I just remembered that my oldest daughter is on our plan with Verizon and is going to Japan soon. I think we purchased a daily plan for each line while we were in the Caymans, I think it was like $10 per line, per day. Will such work well for her while in Japan?
A Verizon phone should work in Japan, but the Verizon day pass might not be the best option. You can get cheap eSIM cards from many providers in Japan, but those only work if the phone is unlocked or supports dual SIMs. If she's traveling with other people, it might be better to share the cost of a pocket Wi-Fi device instead. Both of those options only provide data, though. Wi-Fi calling and RCS messages would work, but plain SMS wouldn't.
If she's staying in the big cities, then anything that connects to DoCoMo, Softbank, or AU should be fine. If she's traveling to smaller cities and towns, then she'll want something that connects to DoCoMo or Softbank. If she's going to be away from populated areas a lot, then DoCoMo. I've seen people lately saying that the other, cheaper networks are much better now, but my recent experiences say otherwise. You might want to see who Verizon partners with before going with their daily passes.
And I guess a lot depends on how long she'll be there, too. If it's just a few days, then day passes are probably best. On longer trips, eSIM cards or Wi-Fi routers become more cost effective.
On my last trip, I used a pocket Wi-Fi device from Japan Wireless that connected to the Softbank network. I always had a good, fast 4G connection. It was a bit less than $100 for four weeks and that included airport pickup and shipping back to the provider at the end of the trip. The battery lasted all day without any problems, but they also provided a power bank to recharge if needed.
