The 29-year-old Inman completed the 26-mile, 385-yard course in two hours, 35 minutes, 35 seconds. James Holt of Washington, Utah was second in 2:45:45 and Naoki Kato of Torrance third in 2:46:41.
The 32-year-old Yanko was timed in 2:48:20. Nicole Wilson of Baltimore was second among women in 2:54:33 and Meredith Zohar of North Hollywood third among women in 2:59:08.
A field of 3,000 entered the marathon and another 16,000 the half-marathon in California's largest combined oceanfront marathon and half-marathon, drawing runners from 24 nations and 1,000 cities, organizers said.
The marathon began at 6:25 a.m., just before sunrise, with the wheelchair racers, followed at 6:30 a.m. with the rest of the field, at Pacific Coast Highway at Huntington Street in front of the Waterfront Beach Resort.
The course then quickly passed the Huntington Beach Pier. Miles two through nine went through Huntington Beach's Central Park and miles nine through 15 through the Bolsa Chica Ecological Reserve.
Miles 16 through 25 were on a beachfront running path paved over the sand. The final mile took runners along Pacific Coast Highway to the finish line, also near the Hilton Waterfront Beach Resort.
For the 10th consecutive year, the Surf City USA Marathon served as a fundraiser for the Free Wheelchair Mission, an Irvine-based nonprofit group that builds and delivers specially engineered wheelchairs for the impoverished disabled in developing nations.
Runners raising at least $600 for the Free Wheelchair Mission by race day received reimbursement for their race registration fees.