In 2008, Wei Long had a brief stint with the
Singapore Slingers while the team was competing in the 2008/09 Singapore Challenge Series. In August 2009, Wei Long signed a one-year contract to play for the
Singapore Slingers along with 7 other local players. He scored a season high of 14 points, including 4
3-pointers against the
Brunei Barracudas on 18 October 2009, the opening night of the inaugural
ASEAN Basketball League. On 29 November 2011, Wei Long, together with
Shengyu Lim and
Desmond Oh, formed the first trio of Singaporeans that signed new contracts with the Slingers for the 2012 Asean Basketball League season. For the 2013 season, pursuing a higher education at
Nanyang Technological University, Wei Long signed a new contract with the Slingers with a partial commitment, which sees him missing out on most of the teams' away games. Wei Long switched his No 5 jersey to 8. Despite juggling his commitments between his studies and the team, 2013 became Wei Long's most outstanding season yet. He was nominated for the
AirAsia player of the month for February, averaging 16.5 points in that month. He was also honoured as one of the three best homegrown talents in the
ASEAN region who averaged more than 10 points for their team. On 31 March, Wei Long scored his career-high of 29 points against the Saigon Heat, the most points ever scored by any local player in the team. This performance topped his previous career-high of 20 points against the same team on 17 February 2013, the Singapore Slingers Cancer Awareness night. In 2017, after the game against
Kaohsiung Truth, Wong scored his 1000th ABL career points. After sitting out for the
2017–18 ABL season, he officially signed with the
CLS Knights Indonesia for the upcoming
2018–19 ABL season. It is believed that he is the first Singaporean to play professional basketball outside of the republic. == ABL statistics ==