All three passengers were transported to Stanford Medical Center.
Fire officials say the boaters are from the East Bay, possibly Fremont where they launched their boat.
"Once they reached the open water. The wind and the wind waves started coming in and immediately under their boat and capsized their boat," Menlo Park Fire Chief Chris Pimentel said.
The victims suffered mild hypothermia.
A Coast Guard helicopter crew rescued the three from the water and took them to firefighters with the Menlo Park Fire Protection District.
"Basically, the three victims who were in the water held onto the kayak. The person in the kayak notified the Coast Guard and 911," Pimentel said.
Martine Chirayath watched the team of responders come together. She was happy it ended with lives saved. "I was very impressed with the rescue, it was very efficient. They all showed up," Martine Chirayath said.
All three boaters were wearing life jackets, which officials said was critical in their survival.