Metrolinx introduced its much-anticipated One Fare Program on February 26, 2024, and it took less than two months for the new free transfer system to reach a huge milestone.

The transit agency announced on Tuesday that five million passengers have transferred between the TTC and other participating regional transit systems, a milestone reached on April 19.

Under the One Fare program, commuters can transfer between the TTC and GO Transit, as well as regional transit systems like Brampton Transit, Durham Region Transit, MiWay and York Region Transit — all for a single Presto fare.

Metrolinx touts how adults commuting five days a week can save up to $1,600 per year thanks to the program, and the public has largely welcomed it with open arms.

However, things haven't exactly gone down without a hitch. Many transit users have been making a simple mistake in trying to use paper TTC transfers as proof of payment on other GTA transit systems — a move that, while seemingly logical, can result in hefty fines.

People warn of common One Fare transit mistake that could get you fined in the GTA https://t.co/sWmXnguebM

— theGentries (@theGentries) April 11, 2024

Passengers should be mindful to always tap using a Presto card (physical or Google Wallet), a credit or debit card when transferring systems. Presto will then automatically calculate a 100 per cent discount for valid trips within two hours on local transit and three hours on GO.