During his time at Bay of Plenty, Senio played in a tour match against the British & Irish Lions and was later called into the Junior All Blacks tour of Australia against Australia A. Senio signed a two-year deal with the Canterbury Rugby Football Union (CRFU) on 26 September 2005, making him eligible to play for the Crusaders, after former Canterbury and Crusaders half-back, Justin Marshall, left to play in England following the 2005 British & Irish Lions tour to New Zealand.

Senio also left after playing second fiddle to starting Chiefs' half-back, Byron Kelleher, who is also an All Black.

After being the starting scrum-half for the first part of the season, Senio found himself battling it out for regular game time with rookie Andy Ellis.

However, Ellis was injured in the semi-final against the Bulls and Senio started the 2006 Super 14 Final against the Hurricanes.

The day after the final, Senio was selected for the Junior All Blacks to play in the inaugural Pacific Five Nations tournament.