It's basically the Xperia M2 with added waterproof skills. Like the Xperia Z2, all its ports are sealed, so no water can get in. It's the first time Sony has made a mid-level device with this kind of waterproofing.
It's rated IP65, which means it will be fine for a dip in the pool.
It's no slouch when it comes to the specs, either. A 1.2GHz Qualcomm Snapdragon 400 chip should keep everything running smoothly, and it's 4G, for quicker browsing and downloading.
An 8-megapixel camera sits on the back. But films – Jaws? Titanic? – might not look too crisp on the 4.8-inch 960 x 450-pixel resolution screen. That's much lower than some handsets at this size.
The screen does have in-plane switching (IPS) though, which should make for better viewing angles. Should come in handy if a few of you are crowded around in the pool.
NFC comes as standard, so you can touch to pair with a range of devices including wireless speakers, headsets, and TVs.
It's also compatible with Sony's SWR10 SmartBand, so you can log your day's activities.
The M2 Aqua will be available in black or white, and will go on sale in the Autumn. Which rather misses the swimming pool season. Still, what better excuse for a bit of winter sun?
Read more: Waterproof phones: IP ratings explained