Apollo 11 performed one surface EVA, the mission’s single lunar moonwalk by Neil Armstrong and Buzz Aldrin.
The astronauts landed the Lunar Module Eagle in the Sea of Tranquility on July 20, 1969. After preparing their equipment, Armstrong exited the spacecraft at 02:39 UTC on July 21, followed by Aldrin. Together they spent about two and a half hours outside, taking photographs, collecting lunar samples, deploying scientific instruments, and examining the surface around Tranquility Base.
“Surface EVAs” counts excursions outside the spacecraft on the Moon, not the number of astronauts who went outside. Although two astronauts participated, they did so during one continuous expedition. Michael Collins did not join them; he remained alone in the Command Module Columbia while it orbited the Moon.
Later Apollo missions conducted multiple lunar EVAs, making Apollo 11’s total seem easy to confuse with later missions. Apollo 12, for example, carried out two surface excursions, while Apollo 15, 16, and 17 conducted three each.