| Date/Season | Transaction |
|---|
| 8/25/2022 | St Louis Blues send Joe Hicketts to the Philadelphia Flyers for Mason Lohrei, Mattias Ekholm |
| 8/21/2021 | Chicago Blackhawks send CAR 2027 Rnd 2 to the Philadelphia Flyers for Mattias Ekholm (rental) |
| 7/3/2021 | Buffalo Sabres send Urho Vaakanainenm, Mattias Ekholm, Zach Nastasiuk, Danil Yurtaykin, SJS 2031 Rnd 3, $2,500,000 to the Philadelphia Flyers for Brandon Gormley, Ryan Sproul, Zack Phillips |
| 6/13/2021 | Seattle Kraken send Mattias Ekholm to the Buffalo Sabres for Ethan Werek, BUF 2032 Rnd 1 |
| 4/2/2021 | Seattle Kraken send COL 2026 Rnd 3, $4,000,000 to the Buffalo Sabres for Mattias Ekholm, SJS 2030 Rnd 3 |
| 1/21/2021 | Ottawa Senators send Mattias Ekholm, $200,000 to the Buffalo Sabres for Darcy Kuemper |
| 1/17/2021 | Ottawa Senators send Adam Larsson, Marcus Pettersson to the Calgary Flames for Mattias Ekholm, CGY 2026 Rnd 1, SJS 2027 Rnd 1, SJS 2028 Rnd 1, $2,500,000 |
| 12/17/2020 | Calgary Flames send Jonas Brodin to the Buffalo Sabres for Mattias Ekholm, PIT 2027 Rnd 1, $2,000,000 |
| 9/8/2020 | Calgary Flames send Mattias Ekholm to the Buffalo Sabres for DET 2026 Rnd 2 |
| 2/6/2019 | Calgary Flames send CGY 2023 Rnd 2 to the Philadelphia Flyers for Mattias Ekholm |
| 1/31/2017 | Philadelphia Flyers send Ben Lovejoy to the Florida Panthers for Mattias Ekholm |
| 7/2/2011 | Montreal Canadiens send Chris Phillips, Gerard DiCaire, Mattias Ekholm, Tomas Fleischmann, MON 2015 Rnd 1 to the Florida Panthers for Chris Stewart, Dan Cavanaugh, Jarome Iginla, Robert Czarnik, Troy Brouwer, PIT 2016 Rnd 2, FLA 2016 Rnd 4, DAL 2017 Rnd 3, PIT 2018 Rnd 3 |
| 2018 | Drafted in the 1st round, 24th overall by Florida (from Washington) |
| 2013 | Drafted in the 4th round, 104th overall by Montreal |
