| Apr 26, 2026 | Heidarsson | 0–1 | Heimisson | Boðsmót TR A-flokkur | Queen's Gambit Declined: Vienna Variation, Quiet Variation | |
| Apr 26, 2026 | Hallmundarson | 0–1 | Heidarsson | Boðsmót TR A-flokkur | Sicilian Defense: Najdorf Variation, English Attack | |
| Apr 25, 2026 | Heidarsson | 0–1 | Birkisson | Boðsmót TR A-flokkur | Queen's Gambit Declined: Austrian Defense | |
| Apr 24, 2026 | Omarsson | ½–½ | Heidarsson | Boðsmót TR A-flokkur | Nimzo-Indian Defense: Normal Variation | |
| Apr 24, 2026 | Jonsson | 0–1 | Heidarsson | Boðsmót TR A-flokkur | French Defense: Advance Variation | |
| Mar 25, 2026 | Wadsworth | 1–0 | Heidarsson | Reykjavik Open 2026 | English Opening: Agincourt Defense, Bogoljubow Defense | |
| Mar 6, 2026 | Heidarsson | 1–0 | Hermannsson | Icelandic team chess championship premier league | Semi-Slav Defense: Stoltz Variation | |
| Mar 5, 2026 | Hardarson | 0–1 | Heidarsson | Icelandic team chess championship premier league | Nimzo-Indian Defense | |
| Feb 6, 2026 | Heidarsson | 0–1 | Birkisson | Skákþing Reykjavíkur 2026 | Queen's Gambit Declined: Exchange Variation, Positional Variation | |
| Feb 1, 2026 | Heidarsson | ½–½ | Halldorsson | Skákþing Reykjavíkur 2026 | Nimzo-Indian Defense: Reshevsky Variation | |
| Jan 28, 2026 | Olafsson | 0–1 | Heidarsson | Skákþing Reykjavíkur 2026 | Nimzo-Indian Defense | |
| Jan 18, 2026 | Leosson | 0–1 | Heidarsson | Skákþing Reykjavíkur 2026 | Queen's Indian Defense: Kasparov-Petrosian Variation | |
| Jan 14, 2026 | Heidarsson | 1–0 | Brynjarsson | Skákþing Reykjavíkur 2026 | Nimzo-Indian Defense | |
| Jan 7, 2026 | Heidarsson | * | Ragnarsson | Skákþing Reykjavíkur 2026 | Nimzo-Indian Defense: Normal Variation, Botvinnik System | |
| Jan 7, 2026 | Njardarson | 0–1 | Heidarsson | Skakthing 2026 | Semi-Slav Defense: Stoltz Variation | |
| Dec 7, 2025 | Stefansson | 1–0 | Heidarsson | Friðriksmót Landsbankans – Íslandsmótið í hraðskák | Sicilian Defense: Moscow Variation, Main Line | |
| Dec 6, 2025 | Heidarsson | 0–1 | Stefansson | Friðriksmót Landsbankans – Íslandsmótið í hraðskák | Queen's Indian Accelerated | |
| Oct 25, 2025 | Heidarsson | 0–1 | Szakolczai | Round 7: Heidarsson, Arnar Milutin - Szakolczai, Peter | Benoni Defense: Czech Benoni Defense | |
| Oct 21, 2025 | Heidarsson | 0–1 | Ondozi | Round 3: Heidarsson, Arnar Milutin - Ondozi, Murtez | Queen's Gambit Declined: Exchange Variation, Positional Variation | |
| Oct 20, 2025 | Matyassy | 0–1 | Heidarsson | Round 2: Matyassy, Lazar - Heidarsson, Arnar Milutin | French Defense: Steinitz Variation, Boleslavsky Variation | |
| Sep 12, 2025 | Heidarsson | 1–0 | Hardarson | Haustmot TR 2025 | Queen's Gambit Declined: Exchange Variation, Positional Variation | |
| Sep 3, 2025 | Ragnarsson | 0–1 | Heidarsson | Haustmot TR 2025 | Queen's Pawn Game: Colle System, Traditional Colle | |
| Sep 3, 2025 | Heidarsson | 0–1 | Bergsson | Haustmot TR 2025 | Nimzo-Indian Defense: Normal Variation | |
| Sep 3, 2025 | Sigurdsson | 0–1 | Heidarsson | Haustmot TR 2025 | Sicilian Defense: Alapin Variation, Smith-Morra Declined | |
| Sep 3, 2025 | Heidarsson | ½–½ | Skarphedinsson | Haustmot TR 2025 | Nimzo-Indian Defense: Rubinstein System, Taimanov Variation | |
| Sep 3, 2025 | Gudnyjarson | 1–0 | Heidarsson | Haustmot TR 2025 | Catalan Opening: Open Defense | |
| Sep 3, 2025 | Hermannsson | 0–1 | Heidarsson | Haustmot TR 2025 | Sicilian Defense: Najdorf Variation, Adams Attack | |
| Sep 3, 2025 | Heidarsson | ½–½ | Thorisson | Haustmot TR 2025 | Grünfeld Defense: Three Knights Variation, Petrosian System | |
| Sep 3, 2025 | Bjornsson | ½–½ | Heidarsson | Haustmot TR 2025 | Sicilian Defense: Smith-Morra Gambit Declined, Push Variation | |
| Jun 9, 2024 | Osorio Ferrer | 0–1 | Heidarsson | Round 9: Osorio Ferrer, Roberto Eduardo - Heidarsson, Arnar Milutin | Sicilian Defense: Sozin Attack, Flank Variation | |
| Jun 8, 2024 | Heidarsson | 0–1 | Jonsson | Round 8: Heidarsson, Arnar Milutin - Jonsson, Gauti Pall | King's Indian Defense | |
| Jun 7, 2024 | Heidarsson | ½–½ | Birkisson | Round 7: Heidarsson, Arnar Milutin - Birkisson, Bardur Orn | Slav Defense | |
| Jun 6, 2024 | Birkisson | ½–½ | Heidarsson | Round 6: Birkisson, Bjorn Holm - Heidarsson, Arnar Milutin | Sicilian Defense: Delayed Alapin Variation, with d6 | |
| Jun 5, 2024 | Eliasson | 0–1 | Heidarsson | Round 5: Eliasson, Kristjan Orn - Heidarsson, Arnar Milutin | Sicilian Defense: Closed | |
| Jun 4, 2024 | Heidarsson | 1–0 | Ptacnikova | Round 4: Heidarsson, Arnar Milutin - Ptacnikova, Lenka | Benko Gambit Accepted: King Walk Variation | |
| Jun 3, 2024 | Heidarsson | 0–1 | Skarphedinsson | Round 3: Heidarsson, Arnar Milutin - Skarphedinsson, Ingvar Wu | King's Indian Defense | |
| Jun 2, 2024 | Magnusson | 0–1 | Heidarsson | Round 2: Magnusson, Gisli - Heidarsson, Arnar Milutin | Sicilian Defense: Najdorf Variation, Freak Attack | |
| Jun 1, 2024 | Heidarsson | 1–0 | Johannsson | Round 1: Heidarsson, Arnar Milutin - Johannsson, Markus Orri | Queen's Gambit Declined: Exchange Variation, Positional Variation | |
| Mar 21, 2024 | Heidarsson | 1–0 | Mammadzada | Reykjavik Open 2024 | Queen's Pawn Game | |
| Mar 15, 2024 | Heidarsson | 0–1 | Injac | Reykjavik Open 2024 | Nimzo-Indian Defense | |
| Mar 31, 2023 | Carr | * | Heidarsson | Reykjavik Open | ? | |
| Mar 30, 2023 | Heidarsson | 0–1 | Belenkaya | Reykjavik Open 2023 | Nimzo-Indian Defense: Normal Variation, Botvinnik System | |
| Oct 2, 2022 | Heidarsson | 0–1 | Lindahl | Kvibergspelen 2022 | Modern Defense | |
| Oct 1, 2022 | Heidarsson | 0–1 | Olsson | Kvibergspelen 2022 | Semi-Slav Defense: Normal Variation | |
| Sep 30, 2022 | Heidarsson | 0–1 | Johannesson | Kvibergspelen 2022 | Slav Defense: Exchange Variation, Boor Attack | |
| Feb 24, 2022 | Sjoberg | 1–0 | Heidarsson | Krageroe Resort Chess 2022 | Sicilian Defense: Najdorf Variation | |
| Feb 23, 2022 | Heidarsson | 0–1 | Seo | Krageroe Resort Chess 2022 | Nimzo-Indian Defense: Normal Variation, Classical Defense | |
| Sep 2, 2021 | Kjartansson | 1–0 | Heidarsson | European Individual Chess Championship 2021 - Reykjavik Open | Bogo-Indian Defense: Exchange Variation | |
| Sep 1, 2021 | Heidarsson | 1–0 | Karason | European Individual Chess Championship 2021 - Reykjavik Open | Nimzo-Indian Defense: Sämisch Variation | |
| Aug 31, 2021 | Kanyamarala | ½–½ | Heidarsson | European Individual Chess Championship 2021 - Reykjavik Open | Nimzo-Indian Defense: Normal Variation | |
| Aug 30, 2021 | Maltsevskaya | 1–0 | Heidarsson | European Individual Chess Championship 2021 - Reykjavik Open | Neo-Grünfeld Defense: Classical Variation, Original Defense | |
| Aug 29, 2021 | Heidarsson | 1–0 | Koellner | European Individual Chess Championship 2021 - Reykjavik Open | Philidor Defense: Lion Variation | |
| Aug 28, 2021 | Kjartansson | 0–1 | Heidarsson | European Individual Chess Championship 2021 - Reykjavik Open | Nimzo-Indian Defense: Classical Variation | |
| Aug 27, 2021 | Heidarsson | 0–1 | Kanyamarala | European Individual Chess Championship 2021 - Reykjavik Open | Queen's Gambit Declined: Exchange Variation, Positional Variation | |
| Aug 26, 2021 | Petrov | 1–0 | Heidarsson | European Individual Chess Championship 2021 - Reykjavik Open | Sicilian Defense: Prins Variation | |
| — | Heidarsson | 0–1 | Thorfinnsson | Goðinn 20th Anniversary Open | Queen's Gambit Declined: Exchange Variation, Positional Variation | |
| — | Heidarsson | 0–1 | Ragnarsson | Goðinn 20th Anniversary Open | Semi-Slav Defense: Stoltz Variation | |
| — | Heidarsson | 1–0 | Bjarnason | Goðinn 20th Anniversary Open | Slav Defense: Exchange Variation, Boor Attack | |
| — | Birgisson | 0–1 | Heidarsson | Goðinn 20th Anniversary Open | Catalan Opening: Closed | |
| — | Magnusdottir | 0–1 | Heidarsson | Goðinn 20th Anniversary Open | Sicilian Defense: Smith-Morra Gambit | |
| — | Asmundsson | 0–1 | Heidarsson | Goðinn 20th Anniversary Open | Sicilian Defense | |
