Should we each bring our own carry-on or share one big checked bag?

Each bring a carry-on. Checked bags cost 70-140 dollars each way per bag. You will be on trains constantly. Two small bags are easier than one big bag. You can split up at different activities without bag custody issues.

How do we split souvenirs and shopping between two bags?

Pack a flat foldable duffel bag in one person's luggage. When you buy things, use it as a third bag for the flight home, or check it if it gets too heavy. Costs 70-100 dollars to check on return. Still cheaper than shipping.

Do we need to pack differently if staying in hotels versus Airbnb?

Airbnb usually means laundry in-unit, so pack less. Hotels mean coin laundry or pricey hotel service. Either way, pack for 4-5 days. The difference is convenience, not quantity.

What if we have different packing styles — one light packer, one overpacker?

The light packer carries shared items (toiletries, tech, first aid). The overpacker gets less shared responsibility and deals with their own extra weight. Do not try to change each other. Just allocate accordingly.

Should we bring nice clothes for restaurants?

One smart-casual outfit each covers upscale restaurants and temples. Dark jeans and a collar work for men. Simple dress or nice separates for women. You do not need formal wear unless attending a specific event.

Pack for Two Travelers Going to Japan

Pack one carry-on per person with layering clothes for temperature swings, a shared toiletries kit, and tech adapters for Type A plugs. Japan has excellent laundry infrastructure, so pack for 4-5 days and plan to wash. Coordinate who carries what to avoid duplicate items and maximize space for bringing things home.

Split responsibilities before you pack. Sit down together and assign categories. One person handles all charging cables and adapters, the other carries the first aid kit and toiletries. One packs the laundry supplies, the other carries snacks for the flight. Write it down. This prevents both of you packing sunscreen and neither packing the outlet adapter.
Pack one carry-on each, leave room for expansion. Use a 40-45L backpack or international carry-on roller. Pack it to 70% capacity on the way there. Japan is a shopping destination and you will buy things. If you pack full, you will need to buy another bag or ship items home. Leave the space now.
Layer for 15°C temperature swings between indoors and outdoors. Winter buildings blast heat. Summer buildings blast AC. Pack a light jacket or cardigan you can put on and take off easily. Merino wool base layers work year-round. Avoid bulky single-climate clothes. Think modular: base layer, mid layer, outer layer.
Pack 4-5 days of clothes, plan to use laundry. Coin laundries are everywhere in Japan. Wash and dry costs 500-800 yen per load. Most Airbnbs have washing machines. Hotels often have guest laundry rooms. Pack enough for 4-5 days, wash once during a 10-day trip, or twice during two weeks. Do not pack 14 days of underwear.
Bring one shared toiletries kit in 100ml containers. Japan sells everything, but unfamiliar brands make shopping annoying when you are tired. Bring small containers of what you actually use. One person carries the kit. The other gets the extra luggage space. If you run out, konbini and drug stores are everywhere.
Pack tech together: one adapter set, one power strip, shared cables. Japan uses Type A plugs (same as North America) at 100V. Bring one multi-port USB charger and one small power strip. Designate one person as tech carrier. Coil cables with velcro straps. Put everything in one pouch. Hotel rooms often have limited outlets.
Coordinate shoes to minimize pairs. You each need comfortable walking shoes (you will walk 15,000-20,000 steps per day). One person brings shower sandals for both. Decide if you need dress shoes for nice restaurants. Maximum three pairs per person. Shoes are heavy and bulky.
Pack one day bag that both of you can use. Bring one 20L daypack that either person can carry. Use it for day trips, temple visits, hiking. The other person carries a smaller tote or crossbody for city days. Do not bring two full-size daypacks unless you are doing serious hiking.

Should we each bring our own carry-on or share one big checked bag?: Each bring a carry-on. Checked bags cost 70-140 dollars each way per bag. You will be on trains constantly. Two small bags are easier than one big bag. You can split up at different activities without bag custody issues.
How do we split souvenirs and shopping between two bags?: Pack a flat foldable duffel bag in one person's luggage. When you buy things, use it as a third bag for the flight home, or check it if it gets too heavy. Costs 70-100 dollars to check on return. Still cheaper than shipping.
Do we need to pack differently if staying in hotels versus Airbnb?: Airbnb usually means laundry in-unit, so pack less. Hotels mean coin laundry or pricey hotel service. Either way, pack for 4-5 days. The difference is convenience, not quantity.
What if we have different packing styles — one light packer, one overpacker?: The light packer carries shared items (toiletries, tech, first aid). The overpacker gets less shared responsibility and deals with their own extra weight. Do not try to change each other. Just allocate accordingly.
Should we bring nice clothes for restaurants?: One smart-casual outfit each covers upscale restaurants and temples. Dark jeans and a collar work for men. Simple dress or nice separates for women. You do not need formal wear unless attending a specific event.