San Diego has a habit of converting first-time visitors into repeat ones, and it's easy to see why: warm weather most of the year, a genuinely walkable core, and a list of sights that ranges from world-class wildlife to Cold War naval history — all within reach of the Mexican border.

The biggest draw is the San Diego Zoo, home to more than 4,000 animals across 800 species, including giant pandas. Direct-entry tickets typically bundle the guided bus tour and unlimited rides on the Skyfari Aerial Tram, and the zoo sits right inside Balboa Park — a sprawling green space with 18 museums, ornamental gardens, and striking Spanish Colonial Revival architecture. Much of the park costs nothing to wander; paid extras include the California Tower climb (about $10 with Museum of Us entry) and the Japanese Friendship Garden (around $16). Arrive at the zoo early — the crowds build fast.

Wildlife continues along the coast. La Jolla Cove, part of a protected ecological reserve, hosts a noisy sea lion colony lounging just metres from the cliffside paths, plus harbour seals and bright orange Garibaldi fish in the clear water. It's free, and swimming, snorkelling and kayaking are all on offer nearby. Out on the water, whale watching cruises track migrating gray whales — one popular option sails on a replica of the schooner that won the first America's Cup in 1851, complete with a whale sighting guarantee and snacks included.

History buffs have two strong picks. The USS Midway Museum is a decommissioned Navy aircraft carrier that served nearly 50 years and was once the largest ship in the world — a hands-on, half-day experience rather than a quick plaques-and-out visit. Old Town San Diego covers the city's earlier chapters, with historic streets, small museums and reliably good Mexican food.

For a first visit, a hop-on, hop-off trolley tour is a low-effort way to get oriented: 11 stops covering Old Town, Balboa Park, the zoo, the USS Midway, Little Italy and Coronado, with trolleys roughly every 20 minutes and live commentary on board. Other easy wins: watching the sun go down at Sunset Cliffs, an evening in the Gaslamp Quarter's bars and restaurants, a ghost tour if you like your history spooky, and a guided day trip across the border to Tijuana — one of the few US cities where popping into another country is a realistic afternoon plan.

A sensible three-day split: day one on the trolley plus a Gaslamp food tour; day two at the zoo, followed by a sunset cruise on the bay; day three for brunch, Sunset Cliffs, whale watching and Old Town. One practical note from repeat visitors: you can skip the rental car. Most sights are walkable or reachable by trolley and rideshare, and grouping your days by neighbourhood saves a lot of back-and-forth.

It's a city that suits almost everyone — families get the zoo and beaches, couples get sunset sails and seafood, and anyone with a free afternoon can add a foreign country to their trip.

Original reporting by Destinationless Travel.