Hotel jobs in Japan — how much Japanese do I really need?

Depends on the job. Front desk needs much better Japanese than housekeeping.

Yeah, front desk is hard. Guests ask many different things, and you need polite Japanese.

If you work in housekeeping, basic Japanese may be enough at first.

But even housekeeping needs Japanese for instructions from staff.

I work at a hotel in Hokkaido. My job is mostly cleaning rooms. N4 was okay, but listening was hard at first.
keigo is important. Not perfect, but you should understand common phrases.

Some hotels in Tokyo, Osaka, Kyoto want English too, especially if there are many foreign guests.

For front desk, I’d say N3 is much safer. Not because the grammar is difficult, but because guests don’t always speak clearly. They ask about check-in time, luggage, breakfast, train stations, complaints, lost items, and room problems.

Housekeeping is easier to start with, but don’t think “no Japanese needed.” You still need to understand things like room numbers, cleaning order, towels, amenities, damage reports, and emergency instructions.