Seawater　sea-sand　concrete　(SSC)　has　attracted　increasing　attention　as　an　alternative　to　normal　concrete　due　to　unsustainable　usage　and　overexploitation　of　resources　(e.g.,　gravel　and　river　sand).　The　high　chloride　content　of　SSC　has　hindered　its　widespread　applications　since　the　conventional　steel　reinforcement　is　easy　to　be　corroded　by　the　abundance　of　chloride　ions　in　SSC.　Fiber-reinforced　polymer　(FRP)　composites　that　are　exempt　from　most　corrosion　problems　have　been　introduced　in　the　construction　of　SSC　members.　This　paper　presents　a　series　of　axial　compressive　tests　on　the　square　SSC　columns　wrapped　with　carbon　and　polyethylene　terephthalate　(PET)　FRP　jackets,　the　latter　of　which　are　cost-effective　and　environmentally　friendly　and　have　a　large　rupture　strain　(LRS).　The　experimental　program　included　the　axial　compressive　tests　on　36　square　columns　wrapped　with　PET-FRP　or　CFRP　jackets　and　9　control　cylinders.　Based　on　the　axial　compressive　tests,　the　effects　of　the　SSC　mixing　water　as　well　as　the　type　and　layers　of　FRP　jackets　were　carefully　investigated.　The　measured　stress–strain　curves　of　the　column　specimens　were　compared　with　the　predictions　by　existing　concrete　confinement　models　to　examine　their　reliability　in　predicting　the　compressive　behavior　of　CFRP/PET　FRP-wrapped　square　SSC　columns.　©　2020　Elsevier　Ltd