Most single journeys will go up by between 10p and 30p on April 24.
But the firm claims a massive shake-up in ticketing means thousands who take more than one bus a day could see no increase — and some fares could even go DOWN.
But within Corby, a return from Beanfield to the town centre rises from £2.70 to £4.20 — the same as it costs to get to Kettering and back.
Stagecoach Midlands MD Mark Whitelocks said: "We understand that any increases in costs are unwelcome, particularly when there are wider pressures on household budgets.
"These changes aim to continue simplifying the range of tickets, making bus travel easier to understand.
"There will be customers who see increases to their fares but many will see costs go down or stay the same.
“Like many sectors of the economy, bus operators are seeing significant cost inflation, primarily driven by increased fuel and staffing costs.
"At the same time, the money bus operators receive in fares to keep services running remains significantly below pre-pandemic levels.
“These changes follow a fares freeze for nearly three years and are below the annual rise in inflation."
Across Northamptonshire, the current variety of single fares will be reduced to just six bands and returns replaced by tickets for multiple trips offering better value for money.
Three ticket zones covering Kettering or Corby or both will be replaced with a single Kettering-Corby area with the all-day ticket now 45 percent cheaper at £4.20.
Adding Mawsley into the zone will save villagers up to 52 percent.
The scheme matches those launched in Northampton, Wellingborough and Rushden last year, where daily travel is also capped at £4.20.
MegaRider Gold passes for longer journeys have also been frozen at £9.60 a day while rules on group travel will be simplified.
In Daventry, cross-town singles go DOWN by 10p from £2.10 to £2.00 — but the £3.60 return will go so a round-trip with two singles costs £4.00.