The One Fare program, which allows commuters to connect across multiple Toronto-area transit networks on a single fare, has been in effect for nearly two months now. While it's been widely appreciated, some riders are now warning about one easy-to-fall-into loophole that could get you fined.

With One Fare, residents only have to pay once when transferring between the TTC and GO Transit, Brampton Transit, Durham Region Transit, York Region Transit and MiWay, saving up to $1,600 per year in double fares charged previously.

But, some taking multiple lines have found one common error that could land you a hefty fine for fare evasion, even if you've paid your way.

"I am a transit operator and I've noticed a lot of riders transferring to the 905 regional buses with paper TTC transfers from buses/subway machines. Please DO NOT do this!" a concerned citizen wrote in a Reddit PSA earlier this month, warning of the mistake.

"You need to use Presto/debit/credit. By using a TTC paper transfer, you are committing fare evasion because your ride is technically not free. Although you're not paying a fare when you transfer, the province is paying on your behalf. The only way for the province to pay for your ride is when you tap a Presto, debit or credit card so they can track OneFare transfers."

They proceeded to refer to One Fare as "an amazing program," and asked people to abide by the rules to help keep it running smoothly.

PSA: One Fare Program, please don't do this!
byu/givemean95 intoronto

While paper transfers still work on the TTC — only for one-way continuous trips, mind you — Metrolinx confirmed to theGentries that they are not considered valid on other transit networks participating in One Fare.

"Customers can tap with a Presto card, credit or debit, or PRESTO in Google Wallet to save money with Ontario's One Fare Program," a spokesperson for the agency said.

"Single-ride tickets and paper transfers are not a universal product across all participating transit agencies and therefore cannot be used to transfer between transit systems through the One Fare Program."

Toronto's one fare program is now in effect and this is how it works https://t.co/oYDry2DF34

— theGentries (@theGentries) February 26, 2024

Tapping on (and, when necessary, off) each transit vehicle you take is key not just for your own proof of payment but also for the system itself.

As the operator on Reddit noted, "if you are getting on the same bus day-in, day-out without tapping your card, you are unknowingly costing the system money that is either compensated for by slashing service or raising fares. A lot of people are not understanding the importance of tapping and the financial implications for not doing so."