The grey whale migration passes within sight of San Diego's coast from late November through April, as around 20,000 whales travel south from the Arctic feeding grounds to the lagoons of Baja California and back north again. The migration is visible from the shore at Cabrillo National Monument and Point Loma — binoculars are sufficient on a calm day — but the boat trip brings visitors alongside the whales at close range.
Multiple operators run whale watching tours from the Embarcadero, Broadway Pier, and Shelter Island between December and April. The trips are typically 3–4 hours and depart morning and early afternoon. The peak of the southbound migration is late December through January; the northbound migration in February and March often includes mothers with calves.
Beyond the grey whale season, blue whales feed in the underwater canyon off Point Loma from June through September — this is one of the few places in the world where blue whales are reliably sighted near shore. Dolphin encounters (common dolphins and Pacific white-sided dolphins) are possible year-round.