The 'free wifi everywhere in tokyo' reputation is outdated. Most combini wifi requires japanese phone verification now. Here's what actually works for tourists:

7-eleven still offers 30-minute sessions without verification across shibuya and shinjuku locations. Starbucks harajuku and mcdonald's shibuya crossing have decent free wifi with email signup.

Jr east tokyo metro stations have free wifi but it's slow and cuts out between stations on yamanote line. Don't rely on it for google maps navigation in tokyo.

Better solution: rent pocket wifi at narita airport for ¥500-800/day or get tourist sim. Iij mio sells 7-day data sims at bic camera shinjuku for ¥1500 with 6gb. Way more reliable than hunting for free connections around tokyo station.