Opening a NISA account takes a long time (months!), so you should apply now if you want to start using it in 2018.
It doesn't matter if the account is opened early, you can just not buy anything until 2018 and start using your 2018 allowance then.
Akatani wrote: ↑Mon Aug 21, 2017 7:31 am
Kiyora, I think having to wait til 2018 could be a good thing for you. If you invested in nov of 2017, you'd be burning a full year of tax free gains & dividends. On the other hand, they say investing early is good too. Luckily you don't have to make the choice!
I don't agree with this. Since your plan is to invest 100,000 a month, you're better to start as soon as possible (if you have the money now). You're planning to use your full 2018 allowance, so if you can get some extra in this year too, that's an added bonus
P.S. I started living in Japan in May 2014 and I've been using the NISA since 2015 no problem.