| Jun 26, 2026 | Le Geay | 1–0 | Hallmundarson | Round 11: Le Geay, Joachim - Hallmundarson, Birkir | Sicilian Defense: Nyezhmetdinov-Rossolimo Attack, Fianchetto Variation | |
| Jun 25, 2026 | Hallmundarson | 0–1 | Wijerathna | Round 10: Hallmundarson, Birkir - Wijerathna, Vinuka Dihain | Scotch Game: Mieses Variation | |
| Jun 24, 2026 | Velim | 0–1 | Hallmundarson | Round 9: Velim, Vojtech - Hallmundarson, Birkir | Sicilian Defense: Accelerated Dragon, Modern Variation | |
| Jun 23, 2026 | Hallmundarson | 1–0 | Stefanoski | Round 8: Hallmundarson, Birkir - Stefanoski, Daniel | Semi-Slav Defense: Moscow Variation | |
| Jun 22, 2026 | Ch ng | ½–½ | Hallmundarson | Round 7: Ch ng, Kai Xue Edric - Hallmundarson, Birkir | Queen's Gambit Declined: Orthodox Defense, Rubinstein Variation | |
| Jun 20, 2026 | Hallmundarson | 0–1 | Rusu | Round 6: Hallmundarson, Birkir - Rusu, Lucas | Sicilian Defense: Taimanov Variation, Bastrikov Variation, English Attack | |
| Jun 19, 2026 | Tay | 0–1 | Hallmundarson | Round 5: Tay, Mason - Hallmundarson, Birkir | Sicilian Defense: Grand Prix Attack | |
| Jun 18, 2026 | Hallmundarson | 0–1 | Arun | Round 4: Hallmundarson, Birkir - Arun, Nitish | Queen's Gambit Declined: Westphalian Variation | |
| Jun 17, 2026 | Kazakov | 0–1 | Hallmundarson | Round 3: Kazakov, Barsbek - Hallmundarson, Birkir | Sicilian Defense: Nyezhmetdinov-Rossolimo Attack, Fianchetto Variation | |
| Jun 16, 2026 | Hallmundarson | 0–1 | Vorobyov | Round 2: Hallmundarson, Birkir - Vorobyov, Radmir | Caro-Kann Defense: Advance Variation, Botvinnik-Carls Defense | |
| Jun 15, 2026 | Tuyenbayev | 0–1 | Hallmundarson | Round 1: Tuyenbayev, Amirsan - Hallmundarson, Birkir | Sicilian Defense: Closed | |
| Jun 4, 2026 | Oskarsson | 1–0 | Hallmundarson | Skákþing Íslands - Áskorendaflokkur 2026 | Queen's Gambit Declined: Exchange Variation, Positional Variation | |
| Jun 1, 2026 | Hallmundarson | 1–0 | Karlsson | Skákþing Íslands - Áskorendaflokkur 2026 | Sicilian Defense: Kan Variation, Wing Attack | |
| May 30, 2026 | Hallmundarson | ½–½ | Jonsson | Skákþing Íslands - Áskorendaflokkur 2026 | English Opening: Symmetrical Variation | |
| May 30, 2026 | Birkisson | ½–½ | Hallmundarson | Skákþing Íslands - Áskorendaflokkur 2026 | English Opening: Anglo-Indian Defense, King's Knight Variation | |
| Apr 26, 2026 | Birkisson | ½–½ | Hallmundarson | Boðsmót TR A-flokkur | Yusupov-Rubinstein System | |
| Apr 26, 2026 | Hallmundarson | 0–1 | Heidarsson | Boðsmót TR A-flokkur | Sicilian Defense: Najdorf Variation, English Attack | |
| Apr 25, 2026 | Hallmundarson | 0–1 | Heimisson | Boðsmót TR A-flokkur | Slav Defense: Czech Variation, Dutch Variation | |
| Apr 24, 2026 | Jonsson | 1–0 | Hallmundarson | Boðsmót TR A-flokkur | Sicilian Defense: Accelerated Dragon, Modern Variation | |
| Apr 24, 2026 | Hallmundarson | ½–½ | Omarsson | Boðsmót TR A-flokkur | English Opening: Symmetrical Variation, Three Knights Variation | |
| Feb 15, 2026 | Hallmundarson | ½–½ | Torres | Nordisk Mesterskab gruppe D | Old Indian Defense: Normal Variation | |
| Feb 14, 2026 | Nyberg | 0–1 | Hallmundarson | Nordisk Mesterskab gruppe D | Sicilian Defense: Alapin Variation, Smith-Morra Declined | |
| Feb 14, 2026 | Hallmundarson | 1–0 | Larsen | Nordisk Mesterskab gruppe D | English Opening: Symmetrical Variation, Three Knights, Fianchetto Variation | |
| Feb 13, 2026 | Hallmundarson | 0–1 | Maurstad | Nordisk Mesterskab gruppe D | Sicilian Defense: Kan Variation | |
| Feb 12, 2026 | Lutzen | 0–1 | Hallmundarson | Nordisk Mesterskab gruppe D | Sicilian Defense: Nyezhmetdinov-Rossolimo Attack, Fianchetto Variation | |
| Feb 8, 2026 | Zhang | 1–0 | Hallmundarson | Nordisk Mesterskab gruppe D | Sicilian Defense: Accelerated Dragon, Maróczy Bind | |
| Feb 6, 2026 | Fridjonsson | 0–1 | Hallmundarson | Skákþing Reykjavíkur 2026 | Queen's Gambit Declined: Westphalian Variation | |
| Feb 1, 2026 | Hallmundarson | 1–0 | Ernisson | Skákþing Reykjavíkur 2026 | King's Indian Defense: Normal Variation, Rare Defenses | |
| Jan 28, 2026 | Ragnarsson | 1–0 | Hallmundarson | Skákþing Reykjavíkur 2026 | ? | |
| Jan 25, 2026 | Hallmundarson | 1–0 | Njardarson | Skákþing Reykjavíkur 2026 | Queen's Gambit Declined | |
| Jan 21, 2026 | Halldorsson | 1–0 | Hallmundarson | Skákþing Reykjavíkur 2026 | Catalan Opening: Open Defense | |
| Jan 18, 2026 | Hallmundarson | 1–0 | Ornolfsson | Skákþing Reykjavíkur 2026 | Sicilian Defense: O'Kelly Variation, Normal System | |
| Jan 11, 2026 | Hallmundarson | 0–1 | Skarphedinsson | Skákþing Reykjavíkur 2026 | French Defense: Classical Variation, Shirov-Anand Variation | |
| Sep 7, 2025 | Hallmundarson | 1–0 | Osorio Ferrer | Hautmot T.R - C flokkur | Slav Defense: Chebanenko Variation | |
| Sep 7, 2025 | Hallmundarson | 1–0 | Fridthjofsdottir | Haustmot TR 2025 | Queen's Gambit Declined: Harrwitz Attack, Orthodox Defense | |
| Sep 7, 2025 | Eliasson | * | Hallmundarson | Haustmot TR 2025 | Rapport-Jobava System | |
| Sep 7, 2025 | Grettisson | ½–½ | Hallmundarson | Haustmot TR 2025 | Sicilian Defense: Closed, Traditional | |
| Sep 7, 2025 | Hallmundarson | ½–½ | Leosson | Haustmot TR 2025 | Zukertort Opening: Dutch Variation | |
| Sep 7, 2025 | Ernisson | 1–0 | Hallmundarson | Haustmot TR 2025 | Sicilian Defense: Accelerated Dragon, Modern Variation | |
| Sep 7, 2025 | Hallmundarson | 1–0 | Sigurdsson | Haustmot TR 2025 | Slav Defense: Schlechter Variation | |
| Sep 7, 2025 | Geirsson | 1–0 | Hallmundarson | Haustmót TR 2025 - C flokkur | Sicilian Defense: Accelerated Dragon, Maróczy Bind, Breyer Variation | |
| Apr 12, 2025 | Shafer | 1–0 | Hallmundarson | Reykjavik Open 2025 | Zukertort Opening: Reversed Grünfeld | |
| Aug 20, 2024 | Hallmundarson | * | KORCHEVSKYI | EYCC 2024 Blitz O12 | Queen's Gambit Declined: Neo-Orthodox Variation, Main Line | |
| Aug 20, 2024 | Hallmundarson | 0–1 | Negrean | EYCC 2024 Blitz O12 | English Opening: Symmetrical Variation, Three Knights Variation | |
| Aug 20, 2024 | Hallmundarson | 0–1 | Leenen | EYCC 2024 Blitz O12 | English Opening: Symmetrical Variation | |
| Aug 20, 2024 | Hallmundarson | 0–1 | Filindash | EYCC 2024 Blitz O12 | Réti Opening: Advance Variation | |
| Aug 20, 2024 | KORCHEVSKYI | ½–½ | Hallmundarson | EYCC 2024 Blitz O12 | English Opening: Anglo-Indian Defense, Hedgehog System | |
| Aug 20, 2024 | Negrean | 0–1 | Hallmundarson | EYCC 2024 Blitz O12 | Zukertort Opening | |
| Aug 20, 2024 | Leenen | ½–½ | Hallmundarson | EYCC 2024 Blitz O12 | Nimzo-Indian Defense: Kmoch Variation | |
| Aug 20, 2024 | Filindash | 1–0 | Hallmundarson | EYCC 2024 Blitz O12 | Nimzo-Indian Defense: Normal Variation, Ragozin Variation | |
| Aug 19, 2024 | Hallmundarson | 0–1 | Chiszko | EYCC 2024 Blitz O12 | Queen's Gambit Declined: Three Knights, Vienna Variation | |
| Aug 19, 2024 | Chiszko | 1–0 | Hallmundarson | EYCC 2024 Blitz O12 | English Opening: King's English Variation, Two Knights Variation | |
| Aug 17, 2024 | Hallmundarson | 0–1 | Chiszko | EYCC 2024 Rapid O12 | King's Indian Defense: Normal Variation, Rare Defenses | |
| Aug 17, 2024 | Hallmundarson | 0–1 | Radzimski | EYCC 2024 Rapid O12 | Queen's Gambit Declined: Vienna Variation, Quiet Variation | |
| Nov 26, 2024 | Hallmundarson | 1–0 | Ilcic | Round 11: Hallmundarson, Birkir - Ilcic, Aleksa | Torre Attack: Fianchetto Defense | |
| Nov 25, 2024 | Ritzerveld | 1–0 | Hallmundarson | Round 10: Ritzerveld, Noah - Hallmundarson, Birkir | Sicilian Defense: Accelerated Dragon, Maróczy Bind, Breyer Variation | |
| Nov 24, 2024 | Baturin-Vinogradov | 1–0 | Hallmundarson | Round 9: Baturin-Vinogradov, Miroslav - Hallmundarson, Birkir | Catalan Opening: Open Defense | |
| Nov 23, 2024 | Hallmundarson | 1–0 | Shirinov | Round 8: Hallmundarson, Birkir - Shirinov, Yashar | Queen's Gambit Declined: Cambridge Springs Defense, Bogoljubow Variation | |
| Nov 22, 2024 | Simiyu Jadon | 0–1 | Hallmundarson | Round 7: Simiyu Jadon - Hallmundarson, Birkir | Sicilian Defense: Accelerated Dragon, Maróczy Bind, Breyer Variation | |
| Nov 20, 2024 | Hallmundarson | 0–1 | Elhusseiny | Round 6: Hallmundarson, Birkir - Elhusseiny, Eyad | Queen's Gambit Declined: Orthodox Defense | |
| Nov 19, 2024 | Park | 0–1 | Hallmundarson | Round 5: Park, Onyoo - Hallmundarson, Birkir | Indian Defense | |
| Nov 18, 2024 | Hallmundarson | 1–0 | Italiani | Round 4: Hallmundarson, Birkir - Italiani, Luca | English Opening: Anglo-Indian Defense, Scandinavian Defense, Exchange Variation | |
| Nov 17, 2024 | Yu | 1–0 | Hallmundarson | Round 3: Yu, Zhe - Hallmundarson, Birkir | Sicilian Defense: Nyezhmetdinov-Rossolimo Attack, Fianchetto Variation | |
| Nov 16, 2024 | Hallmundarson | 0–1 | Karthi | Round 2: Hallmundarson, Birkir - Karthi, Jashith | Queen's Gambit Declined: Vienna Variation, Quiet Variation | |
| Nov 15, 2024 | Liam Valambhia | 1–0 | Hallmundarson | Round 1: Liam Valambhia - Hallmundarson, Birkir | Sicilian Defense: Bowdler Attack | |
| Oct 26, 2023 | Hallmundarson | 1–0 | Sahin | WCCC 2023 - Open U10 | Semi-Slav Defense: Meran Variation, Lundin Variation | |
| Oct 25, 2023 | Menke | 0–1 | Hallmundarson | WCCC 2023 - Open U10 | Sicilian Defense: Grand Prix Attack | |
| Apr 7, 2022 | Hallmundarson | 1–0 | Koes | Kvika Reykjavik Open 2022 | King's Indian Defense: Normal Variation, King's Knight Variation | |
| Apr 7, 2022 | Grettisson | 0–1 | Hallmundarson | Kvika Reykjavik Open 2022 | Vienna Game: Stanley Variation | |
| Apr 6, 2022 | Finnsson | 1–0 | Hallmundarson | Kvika Reykjavik Open 2022 | English Opening: King's English Variation, Two Knights Variation, Keres Variation | |
| Sep 2, 2021 | Hallmundarson | 0–1 | Briem | European Individual Chess Championship 2021 - Reykjavik Open | Zukertort Opening | |
| Sep 1, 2021 | Gade | 1–0 | Hallmundarson | European Individual Chess Championship 2021 - Reykjavik Open | Queen's Gambit Declined: Normal Defense | |
| Aug 31, 2021 | Omarsson | 1–0 | Hallmundarson | European Individual Chess Championship 2021 - Reykjavik Open | Queen's Gambit Declined: Exchange Variation, Positional Variation | |
| Aug 30, 2021 | Hallmundarson | 1–0 | Helgadottir | European Individual Chess Championship 2021 - Reykjavik Open | King's Indian Defense: Fianchetto Variation, Debrecen Defense | |
| Aug 29, 2021 | Heidarsson | 1–0 | Hallmundarson | European Individual Chess Championship 2021 - Reykjavik Open | Indian Defense: Anti-Nimzo-Indian | |
| Aug 28, 2021 | Hallmundarson | 0–1 | Maggason | European Individual Chess Championship 2021 - Reykjavik Open | English Opening: Agincourt Defense | |
| Aug 27, 2021 | Jonsson | 1–0 | Hallmundarson | European Individual Chess Championship 2021 - Reykjavik Open | Alekhine Defense: Exchange Variation, Voronezh Variation | |
| Aug 26, 2021 | Hallmundarson | 0–1 | Lubbe | European Individual Chess Championship 2021 - Reykjavik Open | Queen's Gambit Declined: Three Knights Variation | |
| — | Hallmundarson | 1–0 | B. Berglindardottir | Nordic Youth Chess Championship | King's Indian Defense: Normal Variation, Rare Defenses | |
| — | Hallmundarson | 0–1 | Vorobyov | Nordic Youth Chess Championship | Dutch Defense: Leningrad Variation, Matulovic Variation | |
| — | Hallmundarson | 1–0 | Lutzen | Nordic Youth Chess Championship | Semi-Slav Defense | |
| — | Hallmundarson | 0–1 | Bekmukhanov | Nordic Youth Chess Championship | Queen's Gambit Declined: Harrwitz Attack, Two Knights Defense, Blockade Line | |
| — | Hallmundarson | 1–0 | Magnusson | Goðinn 20th Anniversary Open | English Opening: Symmetrical Variation, Four Knights Variation | |
| — | Hallmundarson | 0–1 | Thorgeirsson | Goðinn 20th Anniversary Open | Queen's Gambit Declined: Three Knights Variation | |
| — | Hallmundarson | 0–1 | Thorhallsson | Goðinn 20th Anniversary Open | English Opening: Symmetrical Variation, Four Knights Variation | |
| — | Nieminen | ½–½ | Hallmundarson | Nordic Youth Chess Championship | Sicilian Defense: Nyezhmetdinov-Rossolimo Attack, Fianchetto Variation | |
| — | Lilliehook | 1–0 | Hallmundarson | Nordic Youth Chess Championship | Sicilian Defense: Godiva Variation | |
| — | Heimisson | 1–0 | Hallmundarson | Goðinn 20th Anniversary Open | Catalan Opening: Open Defense | |
| — | Asmundsson | 0–1 | Hallmundarson | Goðinn 20th Anniversary Open | Sicilian Defense: Closed, Traditional | |
| — | Birgisson | 1–0 | Hallmundarson | Goðinn 20th Anniversary Open | Catalan Opening: Open Defense | |