A Half Moon Bay surf instructor says a man named Tim called to set up a lesson for his son and daughter this week.
David Alexander says Tim was in fact U.S. Treasury Secretary Tim Geithner.
He arrived with his kids and another car full of secret service.
The security team stood in the cold on the bluff at Montara State Beach while the Geithners surfed.
Geithner's trip coincided with this week's visit by President Obama.
Alexander says he tried to keep it light and did not talk politics. He did ask Geithner if he plays basketball with the president.
The answer was yes.
Alexander says the economic expert was down to earth and even caught some waves. He says he got a tip but now wishes he asked for investment tips.
"They're a very mellow, nice family," Alexander said. "I never would have thought anything other than he seemed like a businessman. It was fun; I had a great time."
Alexander is still not sure how Geithner chose his surf school, Open Ocean Surfing, but he assumes the treasury secretary found him at his website.