Got February 14 circled in the diary but still without plans? Fear not, we've got it sorted. Read on for some fail-safe ideas on how to impress your loved one.

Discount Suit Company Love Potion London Cocktails
Credit: Courtesy of Discount Suit Company

Stay at a Grown-up Hotel

What about a home away from home—in cozy London—for the night? Check into the Artist Residence late Sunday afternoon and kick back with a couple of cocktails downstairs in The Clarendon Cocktail Cellar. We recommend the Campbell's Tomato Soup, a take on a Bloody Mary made with bacon bourbon. Move on to dinner in the hotel's restaurant, Cambridge Street Cafe (the soft shell crab burger is a hit) and a bottle of red, then enjoy the night in your room, each of which are individually designed and unique. While the hotel isn't strictly "children-free," it sports a grown-up vibe. Tucked away on a quiet street in Pimlico, it's the perfect bolthole for a whirlwind romantic trip.

Colombia Road Flower Market

Nothing says Valentine's Day like flowers, but instead of buying a dud bunch from the grocery store, take a trip down Columbia Road to pick up some of the most beautiful blooms in London. (The flower market only runs on Sundays, but luckily this year, so does Valentine's Day.) It's an experience in itself, admiring the art of the heckling East London traders, and there are plenty more exotic options for purchasing. Follow it up with a low-key yet lovely lunch at Paradise Garage, a seasonal British restaurant tucked into one of the arches of Paradise Row.

Dinner at Sexy Fish

If it's got "sexy" in the title, it's perfect for Valentine's. Sexy Fish, the newest opening from the Caprice Group, is one of London's hottest new restaurants, and with its mood lighting, fine food, and opulent decor (Damien Hirst's mermaids are featured at either end of the bar), it's the ultimate spot for a dinner date. Over Valentine's Day weekend there will be live music performances, a five course tasting menu available throughout the day, and bespoke drinks—Kalamasutra Martini anyone? Sip sake, share plates of yellow tail sashimi, and smooch.

Snorkel with Sharks

After a little more adrenaline than a dinner date? Well, it doesn't get more exhilarating than sharks. Assuming your loved one is a fan (otherwise it could be a rather traumatic time), take them to Sea Life London Aquarium for the Snorkeling with Sharks experience. It is by no means an experience restricted to children; you'll be submerged into the water and separated from the creatures with nothing but a mesh net. The experience lasts an hour and costs $182.

Ride the London Helicopter

London might not be quite as tall as Manhattan, but it's just as impressive from above. Wow a date with a romantic helicopter ride over the city—assuming he or she doesn't have a fear of heights. The London Helicopter is the only company that flies over the capital from a central London location (Battersea to be exact). Of the three tours offered, we recommend the London Sights tour, an 18-minute flight that takes you over Hyde Park, Buckingham Palace, Westminster Abbey, the London Eye, Shakespeare's Globe, yhe Tower of London, and more.

Live jazz at The Wellesley

Woo your Valentine with a sumptuous dinner and a spot of jazz. The Wellesley, one of London's most luxurious hotels, is hosting a five-course meal complete with a decadent Dolce di San Valentino for dessert, on February 13 and 14. Held in the Oval Restaurant and Jazz Lounge, guests can kick back and enjoy leisurely live jazz performances after dinner. Those staying at the hotel in one of the 36 guest rooms can complete their five star stay with a ride in the hotel's Rolls Royce, too.

Drink Love Potion

As Valentine's Day falls on a Sunday this year, it's going to be all about afternoon cocktails. Why not cozy up in Discount Suit Company, an underground drinking den in East London, not far from Liverpool Street station, with the Love Potion #9 cocktail? Designed for two, it features Quiquiriqui mezcal, bold cherry aperitif, and Kamm and Sons Ginseng Spirit. That's a heady combo sure to set sparks flying.

Alice Tate covers London and Europe for Travel +Leisure. Follow her on Twitter and Instagram.