Summary
Jisanaoshi is a planned travel app that, from your departure city, arrival city and flight times, builds a schedule of when to seek and avoid light, when to sleep and when to have caffeine — from a few days before departure until after you arrive — and reminds you at each time.
At a glance
| Status | Under consideration — not released (not on the App Store yet) |
|---|---|
| For | People flying across time zones (about 1.52 billion international trips worldwide), frequent business travelers and crew |
| Main features | A plan from your flight times, light, sleep and caffeine timing, adjustment before departure, timed reminders, a plan for the return flight |
| Devices | iPhone (iOS 26 or later, planned) |
| Languages | English, Japanese and more (planned) |
| Planned pricing | Ad-supported with all features usable (not decided) |
| Data storage | On the device only. Calculations run on the device |
Who it is for and what problem it solves
After crossing many time zones, the body clock takes days to match local time, causing poor sleep and daytime sleepiness. Shifting light exposure and sleep in advance is said to help, but working out what to do and when is hard on your own.
- The direction of the shift changes depending on flying east or west
- It is unclear when to sleep on the plane
- Few dedicated planners are available in languages other than English
Screens and features (planned)
Trip details
- Departure and arrival cities (time difference calculated automatically)
- Flight departure and arrival times, connections
- Your usual bedtime and wake time
- How many days before departure to start adjusting (0 to 3)
Plan
- For each day, bands showing when to seek light, avoid light, sleep and have caffeine
- On the plane, when to sleep and wake in both departure and arrival time
- The first few days after arrival until you are adjusted
Reminders
- "Get light now", "Avoid caffeine from now", "Time to sleep" at the right moments
- Automatic switch to local time
Return trip
- A plan for the flight home in the same way
How it works (planned)
- Enter departure and arrival cities, flight times and your usual sleep times
- Review the plan
- From a few days before departure, shift light, sleep and caffeine as reminded
- Follow the plan for a few days after arrival
Input and output
What you enter
- Departure and arrival cities
- Flight times
- Usual sleep times
- Start day for adjusting
What you get
- A daily plan
- Timed reminders
- Guidance for the flight
How your data is handled
- Trips and plans stay on the device and are not sent to our servers
- No account or sign-in
- Calculations run on the device without a connection (city time zone data is stored on the device)
How it differs from existing apps
- Available in Japanese and other languages
- Shows the plan in both departure and arrival time, including what to do on the plane
- No limit on how many plans you can create (planned, ad-supported)
What this app does not do
- It does not diagnose or treat sleep disorders, or advise on sleeping pills or supplements
- People with medical conditions or taking medication should consult a doctor before use
Frequently asked questions
Is Jisanaoshi available now?
No. It is under consideration and not on the App Store. This page describes the plan.
Is there an app that reduces jet lag starting before the flight?
Jisanaoshi is a planned app that builds a light, sleep and caffeine schedule from your flight times, starting a few days before departure, and reminds you at each time.
Will it tell me when to sleep on the plane?
Yes. The plan shows when to sleep and wake on the plane in both departure and arrival time.
Is it different for flying east and flying west?
Yes. The direction decides whether to shift earlier or later, and the plan is built for your direction automatically.
Does it work offline?
Yes. Calculations are planned to run on the device, so it works on the plane.
Will it tell me how much melatonin or sleeping medicine to take?
No. It gives no advice on medicine or supplements. Ask your doctor.
Other languages
日本語 English 한국어 繁體中文 简体中文 Français Español Português Deutsch Italiano Türkçe العربية ไทย Tiếng Việt Bahasa Indonesia Polski
Last updated: 2026-10-25. This page describes a plan before development. No release date has been set.