Travellers on more than 4,600 routes will now pay no more than that for a single journey until the end of March as part of an effort to take up to two million cars off the road.
And some of the biggest savings will be on long distance routes.
The “Get Around for £2” scheme will take £13 off the cost of going from Leeds to Scarborough in Yorkshire and cut the fare from Lancaster to Kendal in Cumbria by £12.50.
Passengers from Plymouth to Exeter, Devon will save £9.20 and those from Newcastle to Middlesbrough in the North East will see their fare fall by £6. The cost of going from Hull to York will go down by £6.50.
On average, bus fares will be cut by almost a third. The scheme, targeting routes outside London, is designed to address the cost-of-living crisis as well as protecting the environment.
Norman Baker of the Campaign for Better Transport said of the fare reductions: “Affordable bus travel really is a win-win. Capping bus fares in this way will help struggling households, cut traffic congestion and carbon emissions, and inject new life into dwindling bus services.”
More than 130 operators are taking part in the £2 scheme, which is backed up with £60million of government funding. It comes as the average single bus fare for a three-mile journey outside the capital is now around £2.80.
Transport Secretary Mark Harper said: “By helping passengers save almost a third off the average single bus ticket and taking two million cars off the road, the £2 bus fare cap is a fantastic way to start the new year.
“Buses are a key part of our vision for a clean, efficient and modern transport network that is affordable for everyone.”
The scheme is a part of the “Help for Households” campaign and is designed to “deliver real savings for those most affected by the rising cost of living”.
Martin McTague, national chairman of the Federation of Small Businesses (FSB), hopes the reduced fares will encourage people to go on shopping trips.
He said: “More than a third of small firms consider public transport important to their business. It is encouraging to see support on bus fares as we battle tough economic conditions.
“This move will likely encourage shoppers to go to towns and cities – just the fuel we need for economic growth.”
The scheme ends on March 31 but the Government has pledged to “consider future support”.