Swiss pilot Bertrand Piccard completed the 62-hour leg of the journey on Sunday morning after taking off from Kalaeloa airport in Hawaii on April 21st.
Reporting live updates on his journey through twitter and the website solarimpulse.com, Piccard posted images from the cockpit as he approached San Francisco, flying over the famous Golden Gate Bridge.
"Flying over #goldengatebridge will be like passing the finish line. I cannot wave but I'm sure they will see #Si2" he tweeted.
His flight completed the Pacific crossing started way back in July 2015 when the project's second pilot, fellow Swiss André Borschberg, flew a record-breaking five-day solo journey from Japan to Hawaii.
So gruelling was that leg of the journey that it burned out the plane's batteries, grounding it for six months while essential repairs were carried out.
Speaking after Piccard's landing on Sunday Borschberg said: “This flight was a huge step in the adventure and Bertrand Piccard accomplished it like a professional pilot.”
The culmination of 13 years of research, Solar Impulse 2 aims to fly around the world without using a drop of fuel, relying instead on 17,000 solar cells.
It started its journey in Abu Dhabi in March 2015 and has been flown alternately by Piccard and Borschberg, since the tiny cockpit can only accommodate one person.