MESSAGE IN A BOTTLE
Where it lands,
the sea decides
Drift Letter lets you put a letter in a glass bottle and set it adrift off your own beach. The bottle drifts a day at a time on that day’s real current and wind data, and every day the sea adds a note in the margin of your letter about what happened. There is no sign-up, and your letters are stored only on your phone.
01
Write a letter, throw the bottle
Choose your beach, write and seal your letter, then flick the bottle in your hand upward to throw it out to sea. You can send one bottle a day for free.
02
The real sea carries it
The bottle’s path is worked out hour by hour from public ocean forecasts (HYCOM currents and wind, NOAA WAVEWATCH III waves). The sea on screen shows the real waves, wind and sky at that spot, too.
03
The sea’s log
Open the letter and you will find the sea’s own handwriting added to yours: the name of the current, its direction, the distance and the water temperature. When the bottle reaches a shore, it gets a postmark.
The bottle’s path is a simulated drift calculated from real data. Please do not throw bottles or rubbish into the real sea, and do not use the app for safety decisions such as sailing, fishing or swimming.
How the service works
There is a banner ad at the very bottom of the screen. After you have sent today’s free bottle, you can choose to watch one rewarded ad to send one more bottle (up to twice a day). There are no interstitial (full-screen) ads. Drift Letter Premium, a one-time lifetime purchase, lets you send up to five bottles a day with no ads. The app collects limited usage statistics.
Ocean data: HYCOM (US Naval Research Laboratory and partners), NOAA WAVEWATCH III (via PacIOOS). Coastline: Natural Earth (public domain). Beach names: © OpenStreetMap contributors (ODbL). The poems in the lighthouse keeper’s bottles are works whose copyright has expired.
Privacy
What we store, what is sent when ocean data is downloaded, and how to delete it.
Read the Privacy Policy →Terms
What the app offers, the limits of the drift calculation, and payments and refunds.
Read the Terms of Use →Need help?
Reporting problems, deleting records, restoring purchases and privacy requests.
Go to Support →