Twenty20 Batting and Fielding in Each Season by Kevin O'Brien
| Season | | Matches | Inns | Not Out | Runs | HS | Ave | 100 | 50 | Ct | St |
| 2008 | (Ireland) | 4 | 3 | 1 | 26 | 17* | 13.00 | 0 | 0 | 0 | |
| 2009 | (England) | 10 | 8 | 2 | 100 | 39* | 16.66 | 0 | 0 | 2 | |
| 2009-10 | (Sri Lanka) | 3 | 3 | 0 | 17 | 11 | 5.66 | 0 | 0 | 2 | |
| 2009-10 | (United Arab Emirates) | 6 | 6 | 1 | 35 | 13 | 7.00 | 0 | 0 | 2 | |
| 2009-10 | (West Indies) | 3 | 3 | 1 | 24 | 13 | 12.00 | 0 | 0 | 1 | |
| 2010 | (West Indies) | 2 | 1 | 0 | 9 | 9 | 9.00 | 0 | 0 | 1 | |
| 2011 | (England) | 14 | 14 | 2 | 365 | 119 | 30.41 | 1 | 1 | 6 | |
| 2011-12 | (Kenya) | 3 | 3 | 1 | 43 | 30* | 21.50 | 0 | 0 | 1 | |
| 2011-12 | (United Arab Emirates) | 11 | 8 | 2 | 188 | 47 | 31.33 | 0 | 0 | 4 | |
| 2012 | (Ireland) | 3 | 3 | 0 | 5 | 5 | 1.66 | 0 | 0 | 0 | |
| 2012 | (England) | 6 | 4 | 1 | 52 | 22 | 17.33 | 0 | 0 | 4 | |
| 2012-13 | (Bangladesh) | 11 | 10 | 3 | 131 | 30 | 18.71 | 0 | 0 | 3 | |
| 2012-13 | (Sri Lanka) | 2 | 2 | 0 | 48 | 35 | 24.00 | 0 | 0 | 1 | |
| 2012-13 | (United Arab Emirates) | 1 | 1 | 1 | 1 | 1* | | 0 | 0 | 0 | |
| 2013 | (England) | 3 | 3 | 1 | 72 | 54 | 36.00 | 0 | 1 | 3 | |
| 2013 | (West Indies) | 8 | 8 | 0 | 154 | 70 | 19.25 | 0 | 1 | 1 | |
| 2013-14 | (West Indies) | 2 | 2 | 1 | 18 | 15* | 18.00 | 0 | 0 | 1 | |
| 2013-14 | (Bangladesh) | 3 | 3 | 1 | 59 | 42* | 29.50 | 0 | 0 | 2 | |
| 2013-14 | (United Arab Emirates) | 8 | 8 | 1 | 251 | 62* | 35.85 | 0 | 1 | 1 | |
| 2014 | (England) | 10 | 7 | 2 | 91 | 40* | 18.20 | 0 | 0 | 6 | |
| 2014 | (West Indies) | 10 | 9 | 2 | 222 | 90* | 31.71 | 0 | 2 | 7 | |
| 2014-15 | (New Zealand) | 2 | 2 | 0 | 69 | 52 | 34.50 | 0 | 1 | 0 | |
| 2015 | (England) | 7 | 7 | 1 | 160 | 48* | 26.66 | 0 | 0 | 0 | |
| 2015 | (Ireland) | 11 | 9 | 1 | 143 | 36 | 17.87 | 0 | 0 | 5 | |
| 2015-16 | (New Zealand) | 9 | 9 | 1 | 149 | 42 | 18.62 | 0 | 0 | 3 | |
| 2015-16 | (United Arab Emirates) | 1 | 1 | 0 | 23 | 23 | 23.00 | 0 | 0 | 0 | |
| 2015-16 | (Australia) | 2 | 2 | 1 | 19 | 19* | 19.00 | 0 | 0 | 0 | |
| 2015-16 | (India) | 3 | 2 | 0 | 14 | 14 | 7.00 | 0 | 0 | 0 | |
| 2016 | (England) | 9 | 8 | 1 | 115 | 29 | 16.42 | 0 | 0 | 4 | |
| 2016 | (Ireland) | 1 | 1 | 0 | 32 | 32 | 32.00 | 0 | 0 | 0 | |
| 2016-17 | (India) | 3 | 3 | 0 | 19 | 11 | 6.33 | 0 | 0 | 1 | |
| 2016-17 | (United Arab Emirates) | 5 | 5 | 0 | 109 | 40 | 21.80 | 0 | 0 | 1 | |
| 2017 | (Ireland) | 4 | 4 | 0 | 37 | 19 | 9.25 | 0 | 0 | 0 | |
| 2018 | (Netherlands) | 4 | 4 | 1 | 54 | 28 | 18.00 | 0 | 0 | 1 | |
| 2018 | (Ireland) | 10 | 9 | 0 | 94 | 30 | 10.44 | 0 | 0 | 4 | |
| 2018-19 | (India) | 3 | 3 | 0 | 116 | 74 | 38.66 | 0 | 1 | 1 | |
| 2018-19 | (Oman) | 3 | 3 | 0 | 130 | 65 | 43.33 | 0 | 1 | 2 | |
| 2018-19 | (United Arab Emirates) | 2 | 2 | 0 | 23 | 22 | 11.50 | 0 | 0 | 1 | |
| 2019 | (Ireland) | 7 | 7 | 0 | 207 | 63 | 29.57 | 0 | 2 | 2 | |
| 2019-20 | (West Indies) | 3 | 3 | 0 | 88 | 48 | 29.33 | 0 | 0 | 0 | |
| 2019-20 | (India) | 3 | 3 | 0 | 80 | 35 | 26.66 | 0 | 0 | 1 | |
| 2019-20 | (Oman) | 4 | 4 | 0 | 191 | 124 | 47.75 | 1 | 0 | 4 | |
| 2019-20 | (United Arab Emirates) | 8 | 8 | 0 | 141 | 41 | 17.62 | 0 | 0 | 6 | |
| 2020 | (Ireland) | 4 | 4 | 1 | 148 | 82 | 49.33 | 0 | 1 | 2 | |
| 2021 | (Ireland) | 15 | 15 | 0 | 220 | 60 | 14.66 | 0 | 1 | 4 | |
| 2021-22 | (United Arab Emirates) | 6 | 6 | 0 | 151 | 54 | 25.16 | 0 | 1 | 4 | |
| 2022 | (Ireland) | 6 | 6 | 2 | 134 | 64* | 33.50 | 0 | 1 | 0 | |