Across Britain generally, the choice of properties has increased by around a fifth (20%) compared with a year ago, Zoopla said.
Supply has increased particularly strongly in locations including Cornwall; Bournemouth, Christchurch and Poole in Dorset; and North Kesteven in Lincolnshire, Zoopla said.
It added that, across the South West of England, estate agents typically have around two-and-a-half times as many homes for sale as they did in spring 2022.
The website suggests strong house price growth in some locations over the past five years may be prompting some people to sell.
In Cornwall, property prices have increased by more than a quarter (27%) on average, while prices in Bournemouth, Poole and Christchurch have jumped by a fifth (20%), Zoopla said.
There are also signs that the rise in supply is having a knock-on effect on the time it takes to sell a property.
In Cornwall it is typically taking 20 days longer on average to sell a property compared with spring 2022, and 23 days longer on average in Bournemouth, Christchurch and Poole, Zoopla said.
The website also said that, in Wales, locations such as Caerphilly and the Vale of Glamorgan, where people can commute to nearby Cardiff, are also experiencing big jumps in available properties.
In the East Midlands, the increase in supply is particularly pronounced in more rural areas such as southern Lincolnshire and Derbyshire, including the Peak District.
During the coronavirus pandemic, there were signs of a “race for space” in the property market, with many buyers looking to move to more rural and coastal locations.
But the return to office or hybrid working means that some potential buyers may not be motivated to move for a lifestyle change – and sellers need to make sure they set their prices realistically in the current market, Zoopla said.
Izabella Lubowicka, senior property researcher at Zoopla, said: “Affordability continues to impact budgets. Sellers putting their homes on the market need to keep that in mind and ensure they are pricing their property realistically in order to achieve a sale.”
Sam Turner, director at Cornwall-based estate agent Kivells, said: “There has been a large increase in new properties coming to the market, which is giving buyers more choice. This is also assisting the moving process for our vendors as they have more to choose from on their onward purchases.”