All guests onboard the 3,140-passenger vessel can use the gadget, the size of a 10p piece, which offers “a more personalised cruise experience”.

Among its features, OceanMedallion allows guests keyless stateroom access, faster embarkation, crew members to see their preferences and tailor their service accordingly and interactive directions throughout the ship.

Caribbean Princess now also features MedallionNet, which gives guests faster internet streaming speeds equivalent to those on land.

OceanMedallion, which was first unveiled by Carnival Corporation chief executive Arnold Donald in 2017, has no visible technology such as an on-off switch or charging function.

Princess said OceanMedallion would continue to roll out as part of a phased fleet-wide activation plan “with further announcements to be made in due course”.

Jan Swartz, president of Princess Cruises, said: “Having 100% of our guests using OceanMedallion on every sailing of Caribbean Princess is a significant milestone that we are celebrating on the path to fleet-wide implementation.

“Our guests tell us that OceanMedallion is turning an already extraordinary experience on Princess Cruises into an even more spectacular holiday, making sailing on Caribbean Princess the ultimate Caribbean cruise.”