The old coin will officially lose its legal tender status at midnight on Sunday October 15, meaning businesses no longer have to accept it, and you won't be given any in your change.
Tesco has now said it will continue to accept the old coins for an extra week, while Poundland will take them until October 31.
A Tesco spokesperson said: “We’ve been updating our systems ready for the new pound coins, but to help customers who still have the old coins, we’ll continue to accept round pounds at our tills and self-service machines for an additional week.”
Royal Mint are now encouraging all old pound coin owners to spend, bank or donate their coins before the deadline.
Andrew Jones, the Exchequer Secretary to the Treasury said, "The clock is ticking. We are urging the public to spend, bank or donate their old pound coins and asking businesses who are yet to do so, to update their systems before the old coin ceases to be legal tender."
If you miss the deadline though, all is not lost as HSBC, Barclays, Nationwide, RBS, Santander and Lloyds/Bank of Scotland have all told Money Saving Expert that they will swap the coin but for their customers only.
The Post Office have also moved to reassure customers that they will be able to exchange old Â£1s after the 15th, saying: “We would like to reassure anyone who is unclear on what to do with their old Â£1 coins that the Post Office is here for you.
“Thanks to an agreement with all UK high street banks, everyone can deposit old pound coins into their usual high street bank account at their local Post Office branch while visiting us to pay bills, pick up online shopping, collect foreign currency, withdraw cash, deposit cheques or any of the many other reasons to pop in. They can do this even after 15th October.”
The new 12-sided Â£1 coin became legal tender on March 28 2017. The old pound coins are to be melted down to create new ones.