Legal reforms helped to bring down prices of long-distance bus tickets by about 25 percent during 2014-2019, according to the Finnish Competition and Consumer Authority (KKV).
At the same time, state-owned railway firm VR reacted by lowering long-distance train tickets by around 20 percent, KKV said in a report.
The combined effect of the drop in ticket prices saved consumers more than 80 million euros.
Budget bus firm Onnibus first rolled along Finnish roads in 2012, causing significant disruption to the long-distance travel sector, prompting at least one bus company to pull out of the market in 2018.
KKV said knock-on effects of competition reforms were also seen in Helsinki's public transport authority, HSL.
Due to the threat of increased competition, HSL saw fewer bidders, but more favourably-priced contracts, for project tenders, leading to a 40 percent drop in costs for the authority.
That equates to savings of around 25-30 million euros in taxpayer funds every year, according to KKV.
The consumer authority also pointed out that VR's bottom line hasn't suffered due to its lower ticket prices, as the firm has responded to the increased competition by streamlining operations and cutting costs.