The　excessive　extraction　of　river　sand　has　led　to　significant　ecological　issues.　Moreover,　the　environmental　impact　and　resource　demand　of　cement　production　have　increasingly　turned　the　spotlight　on　sea　sand　as　a　viable　alternative　due　to　its　abundance　and　ease　of　extraction.　Concurrently,　alkali-activated　binders,　a　novel　type　of　low-carbon　cementitious　material,　have　gained　attention　for　their　low　energy　consumption,　high　durability,　and　effective　chloride　ion　fixation　capabilities.　However,　they　are　susceptible　to　carbonation.　Introducing　a　controlled　sea　sand　amount　can　raise　the　materials’　carbonation　resistance,　although　carbonation　may　raise　the　concentration　of　free　Cl−　within　the　structure　to　levels　that　could　risk　the　integrity　of　steel　reinforcements　by　accelerating　corrosion.　In　this　context,　the　current　study　investigates　sea　sand　alkali-activated　slag　(SSAS)　concrete　prepared　with　varying　water–binder　(W/B)　ratios　to　evaluate　its　impact　on　flowability,　mechanical　strength,　performances,　and　chloride　ion　distribution　post-carbonation.　The　results　demonstrate　that　the　mechanical　property　of　SSAS　concrete　diminishes　as　the　water-to-binder　ratio　increases,　with　a　more　pronounced　reduction　observed.　The　depth　of　carbonation　in　mortar　specimens　also　rises　with　the　W/B　ratio,　whereas　the　compressive　strength　post-carbonation　initially　decreases　before　showing　an　increase　as　carbonation　progresses.　Furthermore,　carbonation　redistributes　chloride　ions　in　SSAS,　leading　to　a　peak　Cl−　concentration　near　the　carbonation　front.　However,　this　peak　amplitude　does　not　show　a　clear　correlation　with　changes　in　the　W/B　ratio.　This　study　provides　a　theoretical　foundation　for　employing　sea　sand　and　alkali-activated　concrete.　©　2024　by　the　authors.