The Apple AirTag is a miniature tracking device that can be used to find your keys, bag or even your dog. I wondered if I would be able to track an AirTag’s journey as it sailed along a river.

The first thing I needed was a small waterproof container – like this vitamin cannister.

I removed the labels and added a tissue (for a waterproof test).

And left it submerged, upside down, for a few hours.

The good news was that tissue wasn’t wet after this scientific test.

Next, I needed a few items to join the AirTag on its journey.

A ‘message in a bottle’ note and five Euros

Hello – this Apple Air Tag began its journey on Sunday December 12th 2021. The container jumped from Charles Bridge in Prague, Czech Republic.

You can track the journey on and Please return just the Air Tag to:
my address – enclosed five Euros toward postage.

Marty McFly from the movie Back to the Future

I almost used a Lego Ghostbuster until I found this un-opened pack, featuring 1955 Marty – he was a perfect size.

A small bag for the AirTag

Just in case the cannister was punctured. Then I had everything I needed.

Charles Bridge in Prague, Czech Republic

Where better for Marty to start his journey, than the historic Charles Bridge in Prague.

I checked my iPhone could see the AirTag.

And made a short video which culminated in the cannister falling into the Vltava river at about 2:50 pm on Sunday 12th December. For a moment, I thought the cannister would be grabbed by a seagull and become airborne!

First Sighting

I should explain that AirTags don’t have GPS, instead, they rely on pinging a nearby iPhone via Bluetooth – the pinged iPhone then sends the location to Apple and the owner of the AirTag can see the location. I wasn’t sure if the range would be good enough to ping an iPhone from the river – luckily it was.

Someone on the riverbank had an iPhone that pinged the AirTag. It had taken Marty over 30 minutes to travel quite a short distance.

More Sightings

Around 4:30 pm, Marty had travelled about 1km and passed under two bridges.

Around 9pm, Marty had travelled a further 3.5km.

Monday 13th December 1:09 am, Marty was pinged passing under Libeň Bridge (Libeňský most) and had travelled around 5 km in total.

Monday 13th December 9:08 am, Marty had travelled another 4 km – pinged by someone on Vodácká street in the Troja area of Prague.

It’s now Monday 13th December 1.55 pm and there hasn’t been an update on Marty’s location.

Next: Finding Marty Lost in Prague.

Where could Marty go?

The Vltava river is the longest river in the Czech Republic, merging with the Elbe at Mělník. The Elbe winds through Dresden, Meißen, then across the North German Plain, passing along the former western border of East Germany, touching Torgau, Wittenberg, Dessau, Magdeburg, Wittenberge, and Hamburg where it flows into the North Sea.

This could be the start of a long journey for Marty.