Gone are the days of retreating to sky-high penthouses. As more and more travelers seek novelty accommodations, the hospitality industry must find new ways to make headlines. With a rising interest in underwater tourism, innovative companies are rolling out futuristic hotels that allow guests to bed down below sea level. But while some adventure-seekers are enticed by the prospect of sleeping with the fishes, others cringe at the idea of having only thick glass walls separating themselves from the sea and its critters.Luckily, travelers who crave breathtaking ocean views—but don't want to hold their breath—can retreat to a lavish over-water bungalow or floating hotel with striking vistas. For any traveler looking to stay in a submerged suite or a buoyed villa, we've rounded up current and planned hotels that are making a splash.Jules' Undersea Lodge rests 21 feet below sea level in Key Largo Undersea Park's Emerald Lagoon. Unlike other aquatic hotels that made our list, Jules' underseas rooms come with no above-water entrance; guests must enter their quarters by swimming through a through an open hatch in the bottom of the main lodge. Comprised of two guest bedrooms and a living area, the lodge easily accommodates two couples, but can host up to six guests at a time. Accommodations feature an entertainment system, and, of course, a 42-inch window from which to marvel at subsea splendors such as parrotfish, snappers, and angelfish. Prices vary depending on package and group size.When this article was published, no opening date was set. Upon completion, Poseidon Undersea Resort will sit approximately 40 feet below sea level in a 5,000-acre tropical lagoon. The complex will feature 24 underwater suites and one luxury apartment, along with a restaurant, library, spa, theater, multipurpose conference room, and even a wedding chapel. Travelers who prefer sleeping above the water will be able to stay in a lavish beachfront villa or an overwater bungalow. But budget-minded travelers take note: Poseidon's accommodations come attached to a steep price tag. An all-inclusive package, which will include four nights in a lavish beach or over-water villa, two nights in an undersea suite, scuba diving programs, and more, will cost around $30,000 per couple per week.When this article was published, no opening date was set. Otherworldly designs—like those for Water Discus Hotel in Dubai—break the mold for inventive underwater retreats. Once the hotel is complete, it will feature 21 rooms set below sea level. From their private subsea suites, guests will have unobstructed views of coral, starfish, sea anemones, and other marvelous sea creatures. Deep Ocean Technology, the Polish company behind the revolutionary design, showcases blueprints featuring one disc above water and one below that are linked through a vertical shaft. Sure, it may take time for these lavish underwater accommodations to materialize, but for those who've always wanted to explore the depths of the deep blue sea, what could be more alluring than staying approximately 32 feet beneath the waves?The Hotell Utter Inn (also known as Hotel Otter Inn) sits on Lake Mälaren in Västerås, Sweden. Although its bright red exterior appears to bob above water, inside, guests have 360-degree views of what takes place approximately 10 feet below sea level. Hotel Utter Inn does not feature electricity; however, guests have access to a portable gas heater and a 10-liter can of fresh water. Prices start at 1,100 SEK (just under $170 USD) per night. For a breath of fresh air, guests can take advantage of the hotel's boat, which is available to explore a nearby uninhabited island.Overlooking the Maldives' sun-drenched waters are the Conrad Maldives Rangali Island's lavish water villas. Offering complete seclusion and tranquility in a private area of the resort's lagoon, the stilted suites feature their own spa treatment rooms, which include massage beds and a mini gym. Each villa also contains a private sundeck, Jacuzzi, and steps that extend into the lagoon. The villas feature striking ocean views from all angles and showcase thatched roofs, adding to their allure as luxurious, yet rustic outdoor retreats. Those who venture outside their rooms will find an abundance of aquatic activities to choose from, such as diving excursions to the Indian Ocean's pristine reef and manta ray watching at night. And although guests can't lay their head beneath the waves, the hotel's underwater Ithaa restaurant offers visitors a whole new spin on the "See Food" diet. This glass-encased venue located 16 feet below the surface of the Indian Ocean allows diners to revel in 180-degree views of marine life while they savor delectable contemporary European cuisine. Water-villa suite room rates vary by season and villa category.Travelers looking to get away from it all can escape to one of Punta Caracol's nine stilted cabins overlooking the Bocas del Toro archipelago in Panamá. Punta Caracol's solar-powered "acqua lodges" come equipped with private terraces and palm leaf roofs. Guests craving an outdoor adventure can spend their time snorkeling along coral reefs. Those who would rather skim the waves than dive beneath them can wake board or surf, among other aquatic activities. Room rates vary according to season and suite type.King Pacific Lodge, a wilderness resort perched on British Columbia's Princess Royal Island, features 17 spacious guestrooms and suites showcasing wilderness or ocean views. Guests staying in ocean view rooms will be treated to awe-inspiring vistas overlooking Barnard Harbor and Whale Channel. Once guests settle into their sumptuous suites, they can participate in a wealth of attractions, from fly-fishing to sea kayaking to whale-watching. And after a long day outdoors, the lodge's Japanese-themed spa and resort's lavish library make for the perfect places to unwind. Nightly rates vary by occupancy and length of stay. Ocean view room rates start at $5,570 CAD (about $5,685 USD) for three nights; $7,300 CAD (about $7,450 USD) for four nights; and $11,810 CAD (about $11,409 USD) for seven nights. (Note: King Pacific Lodge is closed from October through May.)Hotel CPHLIVING can be found anchored in the heart of Copenhagen city center. Comprised of 12 rooms filled with airy floor-to-ceiling windows, heated floors, and maritime décor, this converted boat is ideal for seafarers attracted to the sound of gentle waves lapping against the hull. Also tailored to sun-seekers, Hotel CPHLIVING features a stylish sundeck with striking views of the city and its harbor. Rooms start at 1,000 DKK (approximately $175 USD) per night.Anchored at the Mannum Waterfront near Adelaide in southern Australia, the Dream Boatel's sleek façade creates a striking contrast with the region's surrounding scenery. The "boatel" features five private suites complete with panoramic waterfront views, high thread-count linens, and contemporary bathrooms. Upstairs in the sky lounge, guests can soak up the area's dazzling vistas while taking advantage of the outdoor BBQ station. Nightly rates cost $180 AUD—approximately $187 USD—per person per night.