He made a fine start to his first game in Durham colours, contributing to a seven run victory over Northamptonshire with an aggressive innings of 46 from 40 balls, whilst also taking 2 wickets from 4 overs. Later the same month, he was named in Australia's Twenty20 International (T20I) squad for the 2017–18 Trans-Tasman Tri-Series, which started in February 2018. He made his T20I debut for Australia against New Zealand on 3 February 2018. He scored a match winning 76 from 46 balls against New Zealand at Eden Park later in the same series. New Zealand posted a mammoth total of 243 with the help of a century from the bat of Martin Guptill. Australia started their innings with David Warner and Short with the pair scoring 121 for the first wicket, including the highest powerplay score of 91 runs. Australia eventually won the match by recording the highest successful chase ever in T20I history, with Short named as the man of the match for his batting performance. In May 2018, he was named in Australia's One Day International (ODI) squad for the series against England. He made his ODI debut for Australia against England on 16 June 2018. In June 2018, he along with Aaron Finch registered the highest ever opening partnership of 223 runs in a T20I match against Zimbabwe which was ended in the final over with Short managing to score only 46 runs off 42 balls while Finch went on to score a world record individual score of 172 off 76 balls. The partnership of 223 between Finch and Short is also the highest partnership for any wicket in a T20I and also marked the first ever instance of a 200+ runstand in a T20I match for any wicket. The partnership was also the second highest ever partnership for any wicket in any form of T20, just behind 229 runs set by Virat Kohli and AB de Villiers. Australia finally won the match by 100 runs, which is their biggest winning margin in T20Is.