can i use my Iphone4s in Japan?

Can I use my iphone 4s from the Philippines in Japan?

I will be moving in japan this april, and would like to know if I can still use my iphone 4s (I specified 4s, because I've read somewhere that some iphone models wont work?) I know I'll be living in japan, but I don't want to buy a new phone yet..

so I have some questions:

1. can i use my iphone 4s in japan (assuming it'll be unlocked/openlined)

2. can i just buy a sim card in japan for now, then use it in my current iphone and transfer the sim card in my new phone (in the future)?

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I don't want a temporary phone/simcard since i will be living in for good.

Thank you in advance Japan-guide!

The iPhone 4s and later models are essentially the same everywhere, so no problem.

Sorry, I missed the second question. Whether you can transfer a SIM from your iPhone to another phone depends on the SIM and the other phone. For example if you get a b-mobile SIM you can transfer it to another phone as long as the other phone is also unlocked (and takes the same SIM format of course).

Thank you very much Firas for replying! And about the second question, I wonder if I could buy a Docomo/SoftBank/Au (either of the 3)sim, I want to use what the local uses.

Au no
Docomo has (had?) a plan for unlocked phones, but it is hard to find on their website, and IIRC not very competitively priced.
Softbank possibly will contract out sim-only plans now, but I don't know what rates apply.

Frankly you're probably best off using a b-mobile sim. The new voice/data plans are a steal and use the excellent docomo network. Just use line for your messaging and no one will know you're not actually on docomo.