The old £1 coin, which was first circulated in 1983, will no longer be legal tender from midnight Sunday, 15 October.
The new 12-sided version that has hi-tech security features, entered circulation in March and is less easy to fake.
It's been a huge task for some businesses to make the switch.
Changing the machines at the Grand Pier at Weston-super-Mare will cost £2,500 alone.
It will not start changing its machines until Monday, giving visitors more time to spend their round coins and reducing the amount of business, or customers, they could otherwise lose.
There are still about 500million of the coins still in circulation and they can still be exchanged at banks and post offices.