The Once Human telephone booth puzzle is just one of the many mysteries you'll encounter while out exploring the post-apocalyptic wilderness of the new open-world survival game. You hear a phone ringing, and upon closer investigation, discover the source to be a rundown phone booth. Sure, you can answer the phone and listen to its message, but it doesn't seem to do anything. 

If you've just started playing you might also want to know how to change worlds in Once Human, but otherwise, here's how to solve the phone booth puzzle, and exactly what you need to do to get your rewards.

Once Human telephone booth puzzle solution

To solve the telephone booth puzzle you need to find all four Deviated Telephone Booths in the Dayton Wetlands area and play the message in each. It's important to note that these messages are only available between 7pm – 6am in-game time, so you'll need to find each booth during that window.

The good news is that they're all fairly close to one another and it's easy to locate each by its purple glow and the ringing phone you can hear when you get close. When you activate the phone, simply choose the play message option and exhaust the dialogue before moving on to the next.

All four locations in the Dayton Wetlands are marked above with a telephone symbol on the map. I've also included a short description of where to find each plus its navigation coordinates, which you can use to find each location via the bottom right-hand corner of your in-game map.

• 6612,-4711 – This telephone booth is in the middle of the farmlands next to an orange tractor and a scarecrow
• 6687,-4650 – This booth is just to the north-east of the last one, above a concrete drainage channel, next to a blue pickup truck and a small house
• 6759,-4685 – This booth is east up the hill from the last just by the side of a curving dirt track among some trees
• 6696,-4819 – This booth is south up the hill from the previous on a small island in the middle of a lake that you can get to via a wooden bridge

After you've visited all four, a chest will appear at 6687,-4697 containing 200 Energy Link, four Stellar Planula, 30 Stardust Source, and two Controllers. With that, you've solved the phone puzzle.