Message in a bottle
Where a bottle thrown into the sea ends up: the paths of 28,728 satellite-tracked buoys
Since 1979, oceanographers have set 28,728 buoys adrift that report their position by satellite. Without its anchor, a buoy drifts almost like a bottle. Pick a beach: the page sets off again every buoy that passed it, each from where it was at the time, and shows you where the sea took them.
Every thread on the map is a buoy
Each of these buoys is a float tied to a sea anchor: a sleeve of holed fabric hanging 15 metres down. The anchor holds it to the current below the waves, so the wind cannot push it about. A satellite fixes its position several times a day.
The anchor usually breaks off before the batteries run out. Without it, the buoy floats on the surface, where the wind moves it too, almost like a bottle. On the map, gold threads are paths drifted without the anchor, blue ones with it. More than half the positions (56%) come from buoys that had lost their anchor.
Where the threads gather into a single bundle there is a current: the Gulf Stream, heading north-east from Florida, or the Kuroshio along Japan.
Throw the bottle
Pick a beach or tap anywhere on the sea. The page finds every buoy that passed within 50 kilometres (60 along the Romanian coast; up to 150 where few passed), starts them all from the day they were there and lets them drift for two years.
From the Hebrides, the sea runs north
Between 1993 and 2024, 46 buoys passed within 50 kilometres of the Outer Hebrides. 27 came ashore within two years: 20 in Britain, 6 in Norway and one on the Arctic coast of Russia, 2,382 km away.
Most of those that left British waters went north-east, up the coast of Norway. Bottles do the same: in 2020 a bottle a schoolgirl had dropped off Peterhead in 1996 was found on Gasvær, an island off Norway, according to UPI.
These are 46 buoys from three decades: they show the direction of the water, not the fate of every bottle.
From Iceland to Russia's Arctic coast
Set adrift on 11 February 2020 west of Iceland, this buoy lost its anchor within three weeks. It rounded the southern tip of Greenland into the Labrador Sea, turned back across the Atlantic, passed 24 km off the Outer Hebrides after 788 days, rode up the coast of Norway into the Barents Sea and came ashore on the Kola Peninsula on 18 June 2023, after 1,223 days.
18,816 km to Malaysia
On 17 November 2005 the ship Jens Maersk set a buoy adrift in the Pacific between Ecuador and the Galápagos. It lost its anchor in May 2006 and drifted west, north of the equator, across the whole ocean; it crossed the date line after 402 days, slipped between Taiwan and the Philippines into the South China Sea and, on 27 March 2008, after 861 days, came ashore in Malaysia. From launch to shore is 18,816 km in a straight line: the longest of all 6,853 buoys that ran aground.
From the Caribbean to a beach in France
Set adrift on 2 April 2006 off Cozumel, south of the Yucatán Channel, this buoy spent about seven months in the Caribbean, with a brief loop into the Gulf of Mexico, then caught the Gulf Stream and passed about 45 km from Miami. It crossed the Atlantic and on 5 December 2008, after 978 days, came ashore on the coast of the Landes in south-west France.
Ten years and 40,009 km, almost the length of the equator
The longest-lived buoy was set adrift on 24 January 1996 off Kamchatka. It lost its anchor after almost two years, drifted around the North Pacific and fell silent on 13 June 2006, some 900 kilometres off California, after 3,793 days. Its daily positions, joined up, add up to 40,009 km; the equator is 40,075.
Where buoys come ashore
Of 28,728 buoys, 6,853 ran aground (24%). The rest did not run aground: 18,710 stopped transmitting, 2,041 were picked up by a ship, and 1,124 were still transmitting in June 2025.
The map shows where they ran aground. By country, the most groundings are in the United States (420), then Japan (336), Australia (315), Brazil (253) and the Philippines (240). Seven in ten (72%) had lost their anchor at least a day before and were floating almost like a bottle.
At the 38 beaches on this page, 302 of the 487 buoys that came ashore (62%) came ashore in the same country as the beach.
Before satellites, people threw bottles
In 1864 Georg von Neumayer, who would go on to found the German naval observatory Deutsche Seewarte in Hamburg, threw into the sea off Australia the first bottle of a programme that ran into the 1930s. Each bottle carried a slip to be sent back to Hamburg; 662 came back.
A 663rd, thrown from the barque Paula on 12 June 1886, was found in January 2018 on a beach near Wedge Island, 180 kilometres north of Perth, Australia. Guinness World Records counts 131 years and 223 days at sea: the oldest message in a bottle known.
In 1914 Captain C. Hunter Brown of the Glasgow School of Navigation released 1,890 bottles. The 315th to be found turned up near Shetland in April 2012, almost 98 years later.
On 10 January 1992 a ship lost a container of 28,800 bath toys in the North Pacific: turtles, ducks, beavers and frogs. Hundreds came ashore near Sitka, Alaska, about 3,500 kilometres away, and the oceanographer Curtis Ebbesmeyer used them to trace the currents.
The sea near you
The map is yours: tap anywhere on the sea, from Brighton to Tierra del Fuego. For the full screen, with a map you can move with your finger: “Map only”.