Cowley, 23, finished this year's Mitre 10 Cup as Waikato's leading No 9 and started their last two matches, which were victories over Hawke's Bay (46-22) and Wellington (28-24).
Stuff reports Cardiff announced the capture of Cowley and former Wales first five-eighth Nicky Robinson on Monday (Tuesday NZ time) - the latter coming out of retirement after hanging up his boots last year.
Cowley will again team up with former Hurricanes and Waikato midfielder Willis Halaholo, who signed a three-year contract with Cardiff earlier this year.
