"The Highway 1 drive is a classic road trip; it's beautiful and so dramatic. But the coastline and beaches here are largely unswimmable; they're so wild. We found if you turn off inland from the coast, there are these really beautiful freshwater rivers that weave through that region, and one of our favorites was Big Sur Gorge, which is a swimming hole only a mile up the river from one of the biggest campgrounds in the area. Still, it felt so tucked away and private - the perfect summer experience on an unforgettable section of Californian coast."

Caroline CLEMENTS

"There's this weirdly charming little town in the south-east corner of the state called Tecopa. It's in the desert, not far from Death Valley National Park, and it gets REALLY hot there in the summer. But in winter (which is when you should go), it's a hot springs town. People come from all over to swim in these natural springs and at caravan parks. It feels like a cinematic experience where you can drive your motorhome in, park it up for a few days, and soak in the hot pools. Some of them are man-made and have little private spa baths, but there are also a couple of natural springs in town that are like hot, muddy baths. It's a bizarre place, but a very unique place to swim."

Caroline CLEMENTS

"Only a few hours out of San Francisco is a town called Calistoga. It's wine country but also hot spring country. Many of the properties here have their own natural springs that feed into their swimming pools, so the water is slightly sulphury and salty. The one that we feature in our book is Indian Springs, which is one of the biggest ones in town. Lots of the little hotels and guest houses have hot springs that you can visit and soak in, then go and visit a winery in the afternoon. But often you have to be a guest at the hotel to swim. The whole experience here is pretty luxurious, amongst the vineyards. It felt like a very Californian experience to us."

Caroline CLEMENTS

“In Gold Country, there's a spot called Highway 49 Crossing near Nevada City, where the highway crosses over the river, so it's not off the beaten track at all. There's this manmade river crossing built over the top, but it's so striking. You can also walk upstream and find more secluded pools, of which there are many, and also a bit of a nude swimming spot, so continue up the trail if you wish.”

"It's hard not to include swims in Yosemite National Park. Dillon, my co-author and partner, spent many years as a guide in Yosemite; this was a spot that he had a memory of but didn't know how to get there because it's not a very popular, publicised spot. It's called Grecian Pools. You're traipsing through these high altitude hikes, and then you jump into icy water, even in the summer, because the waters melt from high up in the mountains. You can slip around on the rocks; it feels so clean and fresh. We were up there by ourselves that day, and it felt really special and immersed in nature. Yosemite is a huge national park, and this is a southern corner near Wawona; we loved that one."

Caroline CLEMENTS

"Southern California is so interesting; most people know Los Angeles and Orange County, but unlike the coast in California, particularly around LA, where there are those big sprawling beaches, the beaches around Laguna Beach are protected little coves, meaning there's more possibility to swim safely. One of our favorite beaches in that area was Treasure Island Beach, which is certainly not hidden. There are these groups of local swimmers, so it felt like a real community spot, even though it was a well-known spot. There are many tide rockpools there and a beautiful botanic garden that runs along the cliff."

Caroline CLEMENTS