Twumasi signed for League One club Peterborough United on a three-year contract on 1 July 2010. He signed from Chelsea on a free transfer.
Northampton Town
Since signing for the team he was a regular member of the first team squad but at the beginning of 2011–12 season he ruptured a cruciate knee ligament in a 3–0 win against AFC Wimbledon and subsequently missed the rest of the season. He has since undergone knee reconstruction surgery. Twumasi was released at the end of the 2012–13 season by Northampton.
On 30 July 2013, Twumasi signed for Football League Championship side Yeovil Town. Twumasi was released by Yeovil at the end of the 2014–15 season following their relegation to League Two.
On 25 June 2015, Twumasi signed for League Two club Newport County. He made his competitive debut for Newport on 11 August, versus Wolverhampton Wanderers in the Football League Cup first round. Twumasi made his league debut for Newport in the League Two match versus Stevenage on 15 August 2015. He was released by Newport on 10 May 2016 at the end of his contract.
Twumasi made what he thought was a one-off appearance for Maidstone United against Bromley in the Kent Senior Cup in September 2016. However, a recent rule change meant that by playing for the Stones, he rendered himself unable to move to a Football League club until the transfer window opened in January 2017, scuppering a proposed move to Cheltenham Town. Twumasi subsequently decided to stay with part-time Maidstone in non league's top tier, the National League, while also setting up a football academy in his home country Ghana. After making a number of impressive appearances for the club, Stones manager Jay Saunders revealed in late December 2016 that he did not expect the player to turn out for Maidstone again, citing that he still had Football League interest and was also busy setting up his academy. However, in early January 2017, Saunders declared that he expected Twumasi to now remain with the club.
Maidenhead United
Twumasi joined Maidenhead United on a permanent deal on 17 November 2018.
International career
Twumasi is eligible to represent either Ghana, where he was born, or England, where he grew up from the age of nine. He represented England at under-16, under-17, under-18 and under-20 levels. Before a match between England under-20s and their Ghanaian counterparts in 2009, Twumasi stated he has no doubts over his allegiance, saying: "The game will be emotional, but I'm English now and that's who I want to play for, so there will be no love lost between us."
Personal life
Twumasi founded the Mirage Football Academy in Ghana.
