Lagenorhynchus obliquidens
Pacific white-sided dolphins sweep into SoCal waters from the open North Pacific each winter in herds of hundreds — occasionally topping 2,000 animals — often mixing with common dolphins and riding the bow waves of whale-watching boats in tandem. A bold pale stripe running from eye to tail and chartreuse "suspender" patches on the flanks make them easy to identify even mid-leap.
Newport & Long Beach operators share daily trip counts — you can see what was spotted before you book. Other operators don't publish daily reports.