Should I choose 5-minute unlimited or true unlimited calling?
If most of your calls are under 5 minutes, the 5-minute tier is sufficient and cheaper. If you frequently have calls over 10 minutes or make 20+ calls per month, true unlimited is likely more economical. The price difference is typically ¥500–¥1,000/month.
What is app-based unlimited calling?
Some carriers (e.g., Rakuten Mobile via Rakuten Link) only apply unlimited calling when you use their proprietary app to dial. Calls made through the standard phone app are billed at normal rates. Note that emergency calls (110, 119) cannot be made through these apps.
Can I keep my phone number when switching to a budget SIM?
Yes. Japan's MNP (Mobile Number Portability) system allows you to transfer your number to any carrier. Request an MNP transfer code from your current carrier, then provide it when signing up with the new carrier. Most major carriers have eliminated the MNP transfer fee since 2019.