1
3,278円 /月
総合スコア: 86
Compare Unlimited Data SIM Plans
The ultimate choice for users who never want to worry about data caps. Note that "unlimited" conditions vary by plan — comparing throttling policies is essential.
¥2,000–3,500/mo No data cap Fair use policy may apply Check tethering limits
5 plans found
2
4,268円 /月
総合スコア: 76.43
3
7,425円 /月
総合スコア: 51.39
8,008円 /月
総合スコア: 46.76
8,448円 /月
総合スコア: 45
FAQ
Are unlimited SIM plans in Japan truly without speed limits?
Virtually no unlimited MVNO plan in Japan operates without any restrictions. Most apply a fair use policy that reduces speeds to around 1Mbps after consuming 10–50GB within a single day or three-day period. Always check both the threshold at which throttling kicks in and the speed after throttling before choosing a plan.
How much tethering can I do on an unlimited plan?
Tethering allowances vary significantly between plans. Some unlimited plans include fully unrestricted tethering, while others cap tethered data at 30–50GB per month separately from device data. If you regularly connect a laptop via tethering outside the home, verifying the tethering policy before signing a contract is essential.
What is the typical monthly cost of an unlimited SIM plan?
In 2026, unlimited plans from Japanese MVNOs and carrier sub-brands typically range from 2,000 to 3,500 yen per month. Competitive options include Rakuten Mobile, ahamo, povo, and LINEMO. Pricing varies depending on whether unlimited calling and 5G access are included.