One entry visitor visa questions and cruising

[gonelbo1]

My wife’s family would like to cruise with us. They have one time entry visas with the kids. Parents have five year visas multiple entry. Will the kids have problems returning to USA on a closed loop cruise (starts and ends in Long Beach)
router login 192.168.l.l.link/
Cruise line says it’s ok but I’m double checking because it’s causing anxiety. They need the one time visa to fly to LAX. How is the cruise treated?