When Apple’s Tim Cook unveils the iPhone 14 next week, there’s one killer feature he’s unlikely to talk up – the ability to send direct messages underwater.

That’s because it’s just been invented.

Researchers at Washington State University (specifically a school at the campus named after a Microsoft rival!) have created an app that can send messages without using Wi-Fi or Bluetooth, both of which are pretty much useless underwater.

The software, AquaApp, works on existing devices such as the Samsung Galaxy S9s they tested it on.

“Smartphones rely on radio signals like WiFi and Bluetooth for wireless communication. Those don’t propagate well underwater, but acoustic signals do,” said research co-leader Tuochao Chen.

“With AquaApp, we demonstrate underwater messaging using the speaker and microphone widely available on smartphones and watches. Other than downloading an app to their phone, the only thing people will need is a waterproof phone case rated for the depth of their dive.”

The app comes with 240 built-in messages useful to divers, with the most common 20 just a tap away.

Make sure your phone is actually waterproof first. (Image: Paul G. Allen School of Computer Science & Engineering / YouTube)

Because conditions underwater are constantly changing, the sending phone first sends a ‘preamble’ message to the recipient device, which runs an algorithm to determine the best settings to receive the message proper, tells the sending device, which then sends it.

Real-world tests showed AquaApp worked up to 30m for sending normal messages and 100m for critical SOS alarms, ” sufficient for most recreational and professional scenarios”.

“The state of underwater networking today is similar to ARPANET, the precursor of the internet, in the 1970s, where only a select few had access to the internet,” said Prof Shyam Gollakota.

“AquaApp has the potential to change that status quo by democratizing underwater technology and making it as easy as downloading software on your smartphone.”

Read more about it here.