best phone plan for 3 week holiday

We are a family of three adults (and one child) travelling to Japan in November. We need to be able to keep in touch when we go in different directions and to use internet on our phones (and hopefully use them as hotspots for our tablets). What is the most economical plan for us to get for two or three iPhones (1X iPhone 4 and 2X iPhone SE)? We wouldn't need many calls and could possibly use skype or messenger for these if we get reasonable data. Looking forward to your advice.

Your best option is to rent a phone, since roaming can be expensive if you use your own data, minutes.
An example is softbank rental, see link below. located in all major airports, English speaking staff and unlimited data use

http://www.softbank-rental.jp/e/rental-plan-ib02.php

Another option is prepaid but you pay per minute and you need to recharge your minutes.

Thanks but I would prefer to buy local sim cards and use our own phones if there is a prepaid data only or data plus calls plan we can buy. I travel quite a lot and that's what I do in other countries. Is that not possible in Japan?

This is a great up to date article about the prepaid sim cards

https://tokyocheapo.com/business/internet/prepaid-cheap-japan-sim-card...

I found a 7gb data sim card in one vending machine at Narita Airport for only 5000 yen. I had never read about the brand before but I took a chance and it worked perfectly. Sadly I dont remember the name. The Sim cards all seem to be based on the giant carriers so you cant really go wrong. Just compare amount of data, days of use and the price.

Some cards require some kind of registration but it is usually just click through.

Thanks so much for the useful information especially the 'Cheapo' site - what a great resource they are! I have contacted b-mobile who responded straight away and my phone is fine for their sim card. That seems like a great way to go.