| Temporada | Equipo | Competición | PJ | G | A | Nota | ||
|---|---|---|---|---|---|---|---|---|
| 2022 | Víkingur Reykjavík | Úrvalsdeild | 0 | 0 | 0 | 0 | 0 | – |
| 2021 | Víkingur Reykjavík | Úrvalsdeild | 19 | 0 | 0 | 4 | 0 | – |
| 2020 | Víkingur Reykjavík | Úrvalsdeild | 12 | 0 | 0 | 2 | 1 | – |
| 2019 | Víkingur Reykjavík | Úrvalsdeild | 10 | 2 | 0 | 2 | 0 | – |
| 2018/2019 | Gençlerbirliği | 1. Lig | 13 | 0 | 0 | 1 | 0 | – |
| 2017/2018 | Aberdeen | Premiership | 21 | 3 | 0 | 3 | 0 | – |
| 2016/2017 | Omonia Nicosia | 1. Division | 8 | 2 | 0 | 3 | 0 | – |
| 2016 | Malmö | Allsvenskan | 24 | 1 | 0 | 7 | 0 | 6.7 |
| 2015 | Malmö | Allsvenskan | 13 | 1 | 0 | 3 | 0 | – |
| 2014/2015 | Rotherham United | Championship | 43 | 3 | 0 | 10 | 0 | – |
| 2013/2014 | Rotherham United | League One | 43 | 0 | 0 | 8 | 0 | – |
| 2012/2013 | Rotherham United | League Two | 33 | 2 | 0 | 5 | 1 | – |
| 2011/2012 | Aberdeen | Premiership | 33 | 3 | 0 | 7 | 0 | – |
| 2010/2011 | Plymouth Argyle | League One | 40 | 1 | 0 | 9 | 2 | – |
| 2009/2010 | Plymouth Argyle | Championship | 32 | 2 | 0 | 5 | 0 | – |
| 2008/2009 | Esbjerg | Superliga | 8 | 0 | 0 | 1 | 0 | – |
| 2008/2009 | AGF | Superliga | 12 | 1 | 0 | 2 | 0 | – |
| 2007/2008 | AGF | Superliga | 24 | 0 | 0 | 0 | 0 | – |
| 2006 | Djurgården | Superettan | 6 | 0 | 0 | 0 | 0 | – |
| 2005 | Djurgården | Superettan | 21 | 0 | 0 | 0 | 0 | – |
| Total | 415 | 21 | 0 | 72 | 4 | – | ||
| Fecha | Desde | Hacia | Tipo | |
|---|---|---|---|---|
| 07 ene 2019 | Gençlerbirliği | Víkingur R | N/A | |
| - | Aberdeen | Gençlerbirliği | Free | |
| - | Aberdeen | Víkingur R | Free | |
| - | Omonia | Aberdeen | N/A | |
| - | Malmö | Omonia | N/A | |
| - | Rotherham | Malmö | Free | |
| 07 ene 2012 | Aberdeen | Rotherham | Free | |
| - | Plymouth | Aberdeen | Free | |
| - | AGF | Plymouth | Free | |
| - | AGF | Esbjerg | Loan |
K. Árnason career history shows progression across clubs and competitions, including club timeline, national team appearances and overall career totals.