The　long-term　durability　of　basalt　fiber-reinforced　geopolymer　concrete　(BFRGC)　in　marine　environments　is　importance　for　the　development　of　sustainable　construction　practices.　This　study　examines　the　long-term　durability　of　basalt　fiber-reinforced　geopolymer　concrete　exposed　to　dry-wet　cycles　and　immersion　treatment　in　marine　conditions.　A　geopolymer　concrete　with　1%　fiber　content　was　prepared　and　subjected　to　dry-wet　cycles　and　immersion　treatments　in　a　5%　sulfate　solution　(Tehmina　et　al.,　2014;　Nasir　et　al.,　2016;　John　et　al.,　2016)　[1-3].　Density　measurements,　ultrasonic　pulse　velocity　tests,　and　uniaxial　compression　tests　were　conducted　on　the　BFRGC　after　various　treatment　durations.　The　mechanical　properties　of　BFRGC　were　compared　with　geopolymer　concrete　without　fibers　in　marine　environments.　Additionally,　the　changes　in　compressive　strength　of　geopolymer　concrete　with　and　without　fibers　in　different　immersion　environments　were　further　discussed.　Using　low-field　nuclear　magnetic　resonance　(LF-NMR)　technology,　the　variations　in　pore　structure　were　also　analyzed.　The　results　show　that　the　mechanical　property　loss　from　dry-wet　cycles　was　greater　than　from　immersion　treatment.　In　BFRGC,　strength　decreased　by　10.1%　after　192　days　of　dry-wet　cycles,　compared　to　a　smaller　decrease　of　5.6%　in　immersion　environments.　The　inclusion　of　basalt　fibers　effectively　enhances　stability.　When　in　dry-wet　cycle　tests,　BFRGC　strength　decreased　from　49.6　MPa　to　44.6　MPa,　a　reduction　of　10.1%.　Conversely,　geopolymer　concrete　without　fibers　dropped　from　49.7　MPa　to　42.1　MPa,　a　reduction　of　15.5%.　LF-NMR　test　results　show　that　the　porosity　of　geopolymer　concrete　without　fibers　increased　by　21.6%　and　17.5%　in　dry-wet　cycles　and　immersion　environments,　respectively.　In　contrast,　the　porosity　of　BFRGC　increased　by　16.1%　and　12.7%.　©　2024　The　Authors