Claire Eason, 55, used a garden rake to carve out the 300ft long picture which is so huge it can be seen from space.
The retired GP came up with the idea after spotting the seal-shape hidden in the natural formation of an inlet on Beadnell Bay in Northumberland.
Claire said: “I am always keen to use the natural shapes for my artwork and I often use aerial images for inspiration.
“I’ve been to Beadnell hundreds of times over the years but I’ve never noticed that an inlet leading to a bridge at the far side of the beach resembles the outline of a seal.
“This area is well known for seals and there are thousands living at the Farne Islands which is just off the coast.
“I drew a sketch of the seal on a piece of paper and headed up to the beach with my trusty garden rake.
“It took a few hours to complete and I had no idea whether it would work until I got my drone up to see the whole picture but I was delighted with the result.
“What was most incredible was that I hadn’t realised there was a much smaller shape of a seal pup just under the larger one so unbeknown to me I had a mother and her baby in the same image.”
The nearby Farne Islands are home to 2,737 seals - England’s largest seal population.