The animal stopped briefly on shore on North Ronaldsay on Thursday night before arriving on Sanday, where he is now taking a rest.
Rangers on Sanday have described the walrus as a “magnificent beast” and local schoolchildren have christening him Wally.
Just over five years ago, there was a “once-in-a-lifetime” sighting of a walrus in Orkney but a second animal has now made the journey from the Arctic region.
Lewis Hopper, of the North Ronaldsay Bird Observatory, was out walking his dog on Thursday night when he spotted sight of the mammal in the water.
He said: “I went for a walk around the coast and I was looking at a group of gulls I was interested in. Then I saw the back of the walrus coming out of the water.
“I ran to the coast and I could see it breaching out of the water, and I could see the tusks. My stomach dropped and I thought, ‘Oh my word’.
“I ran round the corner where it was heading and it came up on the beach, where it stayed for around 30 seconds.
“I had a good look at it and it looked straight back at me. Then it slipped back into the water.”
Mr Hopper said the walrus was around three metres long with “a lot of blubber and wrinkles”.
Yesterday morning, the walrus was spotted on Sanday, the next island to the south, on the beach between Sandquoy and Tafts where crowds gathered through the day, including children from the local school.
Mr Hopper said it was unusual to see walruses outside the Arctic circle, saying that even Iceland would be considered “a long journey” for the creature.
The last walrus spotted on North Ronaldsay stayed in the area for only a day or so.
A spokesman for the Scottish Association for Marine Science, which is based in Oban and is affiliated to the University of Highlands and Islands, said it was likely that the walrus had simply got lost.
While the arrival of a walrus in Scotland is extremely rare, there have been at least 13 recorded sightings of walrus in Shetland since 1815, according to Hugh Harrop, director of Shetland Wildlife.
Mr Harrop said: “The walrus is still a vagrant to the UK. It’s best to think of animals as pioneers looking for new habitats.
“These animals can survive for many weeks or even months without feeding.
“They have extortionate amount of blubber under the skin which they can survive on. They usually eat clams and occasionally feed on fish.
“Like seals, the walrus is a very sociable animal which is typically found in numbers. A solitary walrus is not the norm.”
Mr Harrop said he expected the walrus to soon slip back into the water and swim off.
“We are actually hoping it comes to Shetland. There is a lot of interest in it.”
Walruses usually herd together on ice floes and on shore, with hundreds sometimes coming together at one time to sunbathe.
Herds are usually split by the sexes but mating season can bring aggression, with the male fighting his associates to win dominance over the herd.
Despite their size, walruses can move surprisingly fast on land and match the running speed of a human, since they run on all fours like a dog, according to Oceanwide Expeditions.
In water they’ll swim between four miles and 20 miles per hour.