Capsule hotels can be intimidating solo but some are genuinely great for female travelers. The key is picking women-only floors or fully segregated buildings.

Book and bed in shinjuku has a women-only floor that feels like a library sleepover. ¥4500/night including breakfast and it's designed by actual women for comfort and safety.

Nine hours in shinagawa is clinical but super clean and secure. Separate entrances for men/women, great for early flights since it's near haneda train connections.

Avoid the party-focused ones in shibuya - they're loud and primarily male clientele. Stick to business districts where capsule hotels cater to professionals, not backpackers looking to party.