On 20 February 2019, he won a Sigerson Cup medal after lining out at full-back in the 0-16 to 1-09 win over St. Mary's University College in the final.
[3][4] By this stage Flahive had joined the Douglas senior team, having made his debut in a 0-09 to 0-05 win over Newcestown during the 2014 Cork County Championship.
[5] Once again eligible for the grade the following year, he was appointed team captain and was at full-back when Cork suffered a 2-17 to 2-13 defeat by Kerry in the 2014 Munster final.
[8] On 27 January 2018, Flahive made his first appearance for the Cork senior team when he lined out at right wing-back in a 3-16 to 1-16 defeat by Tipperary in the opening round of the 2018 National League.
[11] After a second successive Munster final defeat by Kerry in 2019, Flahive claimed his first senior silverware when Cork secured the delayed National League Division 3 title after remaining undefeated for the entire campaign in 2020.