4g in rishiri/rebun?

hi, we are travelling to hokkaido in may-june and are looking to purchase a SIM card with 4g for our travels. we are going to wakkanai/rishiri/rebun/asahidake onsen/toya/sapporo.

are there any recommended SIM card brands that would be best, especially for the islands of rishiri/rebun? thank u!

here, although many people ask which one is the best, in Japan, only 4 companies (brand name) are there : docomo, au, softbank, and rakuten.
area coverage is the highest, docomo >= au > softbank > rakuten, the lowest.
choose docomo, if you worry about.

Hi Ken, thank you so much. we will go ahead with Domoco then. But are all 4 of them generally fine in terms of internet connectivity?

if you mean "quality", all may be the same when the signals are strong enough.
if you mean "coverage of the area", they are different.
because you go to a rural area, the coverage is a key for you.

Thanks Ken, that's very helpful. :)