Coral　sand　is　characterized　by　the　unique　properties　different　from　conventional　sediments.　To　investigate　the　horizontal　bearing　characteristics　of　2　×　2　pile　groups　in　coral　sand　foundation,　a　series　of　centrifuge　model　tests　were　conducted,　focusing　on　the　effects　of　pile　spacing　and　vertical　dead　loads.　In　this　study,　the　load–displacement　responses,　bending　moments,　lateral　deflections,　and　axial　force　variations　were　measured.　Additionally,　soil　resistance,　p−y　curves,　and　p-multipliers　were　calculated　and　analyzed.　Results　show　that　increasing　pile　spacing　from　3　to　5D　and　7D　enhanced　the　bearing　capacity　of　the　pile　group　by　24.7%　and　77.0%,　respectively.　Compared　to　the　leading　pile,　the　rear　pile　exhibited　reduced　bending　moments,　increased　lateral　displacements,　and　lower　soil　resistance　and　p-multipliers　due　to　pile–soil–pile　interaction　and　the　shadowing　effect.　Furthermore,　the　applied　vertical　dead　load　amplified　the　lateral　displacement　and　bending　moments　of　pile　due　to　the　P−Δ　effect　while　enhancing　soil　resistance　and　increasing　p-multipliers　through　vertical　compression.　These　findings　provide　valuable　insights　for　future　experimental　and　theoretical　research　on　pile　groups　in　coral　sand　foundations.　©　The　Author(s),　under　exclusive　licence　to　Springer-Verlag　GmbH　Germany,　part　of　Springer　Nature　2025.