Aruba, Jamaica, Bermuda, Bahamas — been there, done that. What about the islands that lie more off the beaten track, the ones that don't exactly ring a bell? Allow us to introduce you to seven tropical islands where the beaches, reefs, wildlife and other attractions exist happily off the radar. Book a ticket now, before the secret gets out.

Koh Lipe, Thailand
Remote islands you've never heard of: Koh Lipe, Thailand
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The island has been dubbed the Maldives of Thailand, but, despite its white sand and turquoise water, Koh Lipe remains relatively uncharted in southern Thailand's Andaman Sea. Just 35 miles from Langkawi, Malaysia, this tiny isle exudes low-key allure — no international hotel chains or even cars here (hail a bike taxi to get around, or just walk). Travelers adventurous enough to visit will find small resorts, a few beaches and a fleet of traditional longtail boats standing by to whisk them off to neighboring islets, snorkeling spots and Tarutao National Marine Park.

Milos, Greece
Remote islands you've never heard of: Milos, Greece
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The Cycladic island of Milos is far less known than the famous statue that was discovered here in 1820: Venus de Milo. Suspended halfway between Athens and Crete in the Aegean Sea, this volcanic isle shelters 80 beaches and a mineral-rich moonscape of white rock and cobalt ocean. Academic types will nerd out over Milos' historical attractions, including early Christian catacombs, an ancient Roman theater and a mining museum with local artifacts dating to the Neolithic Age.

North Stradbroke, Australia
Remote islands you've never heard of: North Stradbroke, Australia
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Located near Brisbane, North Stradbroke is the world's second-largest sand island, but laid-back Straddie (Minjerribah to the local Aboriginal people) sees only 24,000 visitors a year. Naree Budjong Djara National Park covers half of this subtropical outpost, and wildlife (wallabies, kangaroos, koalas and one of the most concentrated migrations of humpback whales in the world) is prolific. Must do: Explore the island's rugged beaches, and get your daily steps on the scenic North Gorge Walk.

Rosario Islands, Colombia
Remote islands you've never heard of: Rosario Islands, Colombia
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The day trip to the remote Rosario Islands — a rustic archipelago off the coast of Cartagena, Colombia — begins with a wild ride in a "go-fast boat." Once on Playa Blanca, however, the scene becomes much more relaxed. Rent an umbrella, and when a vendor comes around with a wheelbarrow full of whole coconuts and other coco loco cocktail ingredients, take advantage. For an extra fee, you can stop at an aquarium with dolphin shows on the way to the beach.

Saona, Dominican Republic
Remote islands you've never heard of: Saona, Dominican Republic
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Visitors to the Dominican town of Bayahibe learn a little secret: Saona, the largest island off the coast of the DR, is the day trip of dreams. Not a single hotel exists on this this 42-square-mile isle, part of Parque Nacional del Este (National Park of the East), and only one small village is inhabited. Come to enjoy the sugar sand and postcard palm trees; stay for the chance to see red cushion sea stars in the clear, waist-deep waters of the Natural Pools. (Look but don’t touch: it may be tempting to take a selfie with one of these creatures, but it can harm — or eventually endanger — the species.)

Niue, South Pacific
Remote islands you've never heard of: Niue, South Pacific
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Tonga, Samoa and the Cook Islands get a lot more airtime than their other Polynesian neighbor, Niue, one of the largest raised coral atolls in the world. A self-governing country in free association with New Zealand, this small island is home to 14 villages, a single full-service resort, and one of the most extensive cave systems in all of the South Pacific. Tip: Travel between July to October to swim with whales and dolphins.

Caladesi Island, Florida
Remote islands you've never heard of: Caladesi Island, Florida
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If you follow Dr. Beach's annual lists of America's best beaches, you may have heard of Caladesi Island, which made the cut in 2006, 2007, 2008 and 2016. Otherwise, you're likely unaware of this state park off of central Florida's Gulf coast. To get there, take the ferry from Honeymoon Island State Park, and expect minimal amenities — a snack bar, a bathroom and some picnic pavilions are the only manmade structures in this natural landscape of white sand, coastal dunes and rustling sea oats. For extra credit, rent a kayak and paddle through the mangroves.