Obuya represented Kenya at Under-19 level and played for Kenya in the 1998 Under-19 Cricket World Cup and 2000 Under-19 Cricket World Cup. He was also taught spin bowling by the then head coach of Kenya Under19 side Balwinder Sandhu during the U19 World Cup tournaments. He was later picked in the Kenyan senior squad. He made his ODI debut on 15 August 2001 against the West Indies. He was included in the Kenyan squad for the 2003 Cricket World Cup whereas Kenya also hosted few matches during the course of the tournament. He subsequently made his debut World Cup appearance during the tournament. He picked up 13 wickets at a decent average of 28.76 in the 2003 World Cup and took a career best 5 for 24 in Kenya's win over Sri Lanka at Nairobi, their first victory over Sri Lanka in ODIs. Kenya's dramatic victory over Sri Lanka was considered as a massive upset in world cricket and Kenya subsequently reached semifinals of the tournament. His 5/24 remains the best bowling performance for Kenya in World Cups and he was awarded the man of the match for his match winning performance. During the 2003 World Cup campaign, he received advice and bowling tips from Australian leg spinner Shane Warne. However, Kenyan cricket team quickly faded away following the successful 2003 World Cup. He was later snubbed from the team due to his inconsistent performances and toured Australia in 2005 to work on his bowling skills. He was recalled to the side in 2006 for a four match ODI series against Bangladesh in Bangladesh. He along with his brother David signed a sponsorship deal with Kenya based office equipment supplier CopyCat prior to the 2007 Cricket World Cup, at a time when the national team itself did not have an official sponsor. He made his T20I debut on 1 September 2007 against Bangladesh during the 2007 Kenya Twenty20 Quadrangular tournament. His debut came in Kenya's inaugural T20I match and also marked Bangladesh's first T20I match. He was also picked for the inaugural edition of the ICC Men's T20 World Cup in 2007 which was held in South Africa. His finest ODI innings to date has been an unbeaten 98 against Australia at the 2011 ICC World Cup despite being ended up in a losing cause. The innings cited as one of the best ODI innings by a Kenyan against