Porting phone & bank account for Indian

Hello,
I Will be moving to Japan in first week of November and I am coming from India.

I have some questions as this will be my first time moving out of India.

I am coming to Japan for work and will hopefully be working for at least 2+ years.

I have 2 SIM in India (Airtel and Jio) and I would like to keep both active and use them. At least keep them active because these are linked to everything like bank account, email etc.

How can I keep these SIM active? Just keep paying yearly plans and not use the SIM? Because I might receive OTP and all this SIM that would be extra cost for international SMS.

And what about my Indian bank account? Should I close my salary account? Or can I keep it open and maintain them?

What would be my best move? I hope someone can guide me.

Thanks.

Phone
If you want to keep using your Indian SIM cards for OTP and other purposes, then you have to activate roaming service with your telco in order to access the service/partner in Japan. That means keep paying/subscribe to your Indian SIM cards.

OR check if your banks allowed registration of foreign/overseas phone number, which then you can just use your Japanese phone number, if you plan to get it.

Bank account.
Why would you want to close your Indian bank account? Where/what are you going to do with the money?
Just keep it open, maintain it so that you can/have access to cash/banking when you go back to India for vacation or permanently. Also you can remit/transfer your money in Japan to your Indian bank account.
Save you the trouble to reapply for bank account if you go back in the future. Again that is Indian side matters. Check with your Indian bank.

Should I close my salary account?
Are you being paid in Japan or India?

I did not know that I could receive SMS on roaming without having to pay international roaming fee. I think I'll keep my SIMs active, at least for the time being.

And as for banking, I read that I could convert my bank accounts to NRE and NRO types to maintain them and keep the international transactions going in. My main reason for closing my salary account is that why keep an extra account open when I'm not going to get any money in it.

I should've mentioned this before, but I've got 2 bank accounts, one for salary and other one for expenditure. I'll probably close that salary account because it'll serve no purpose in next 3 months
I'm being paid in India currently, but once I move to Japan, I'll open a Japanese Bank account.
Since most of the banks require the foreigners to be in Japan for at least 6 months, I'll look for some banks that do allow less than that and will obviously talk to my employer about that.

Thanks for taking time to share your thoughts.