The NGO said that two of eight giraffes stuck on the island had now been rescued and the remaining animals are set to be moved in the next few months.
The Rothchilds giraffes were sent to the remote area in 2011 over fears they would be targeted by poachers, but became stranded from the mainland after recent intense rainfall.
Kenya Wildlife Service (KWS) coordinated the daring rescue and was joined by Save Giraffes Now and the Northern Rangelands Trust (NRT).
For years, Rothchilds giraffes have freely roamed Kenya’s Rift Valley, but numbers have declined rapidly, partially due to poaching.
There are now only around 800 left in Kenya and fewer than 3,000 in all of Africa.
Susan is the name of the other giraffe who was saved by the groups. The four remaining adult females, Nkarikoni, Nalangu, Awala and Nasieku, one adult male, Lbarnnoti, and juvenile female Pasaka will be moved early next year.
David O'Connor, president of Save Giraffes Now, said: "There is great urgency to execute this rescue.
“We couldn't have asked for a better result, and we're eager to move the others soon. With giraffe undergoing a silent extinction, every one we can protect matters.”
The giraffes are being moved to the Ruko Community Wildlife sanctuary, where they will gradually be ingratiated into the surroundings.