What is the single most important thing to do on Day 1 in Japan?

Register your address at City Hall (市役所/区役所) and get your current address printed on the back of your Residence Card. This unlocks bank accounts, phone contracts, and most other services that require a Japanese address.

What order should I complete setup tasks during my first week?

Day 1: Address registration at City Hall + get a SIM card. Days 2–3: Apply for a bank account (Yucho app or SBI Shinsei). Days 4–5: Set up health insurance and pension at City Hall. Days 6–7: Research housing if needed, and set up utilities in your apartment.

Can I do address registration and phone/bank setup on the same day?

Address registration takes 30–60 minutes and can be done first thing in the morning. After that you can apply for a Mobal or GTN SIM the same day. Bank account applications (Yucho Tetsuzuki App) can be started immediately but the card arrives 1–2 weeks later.

What should I do if City Hall is closed when I arrive (weekend/holiday)?

You can still get a SIM card (GTN Mobile, Mobal). For address registration, you can submit a "移入届" (move-in notification) at the night-drop box at some City Halls, but most require a weekday visit. Plan to go the next business day.

Do I need to speak Japanese to complete the first-week setup tasks?

Not for most tasks. Mobal and GTN SIM are available in English. The Yucho Tetsuzuki App supports English. SBI Shinsei has English online banking. City Hall address registration is in Japanese but usually takes only 10–15 minutes and staff will guide you through the forms.