Hi Tom - We are looking at what I suspect might be the same Nautica Med cruise in 2025 as well. We are from New Zealand and have cruised 6 times previously with Oceania, all on the smaller R class ships as they tend to do the more exotic and longer itineraries that attract us, although we would love to do a trip on one of the O class ships…!
The passenger mix on the trips we have done has been pretty wide, Americans in the majority but lots of Canadians, Aussies and Brits. It does attract an almost exclusively English as a first language crowd
although when cruising the Med that mix may change a little.
You will find the passengers typically well travelled and we have met some wonderful people. You will find the entertainment and late night activities a little more restrained than you might be used to on the bigger mainstream lines and the bathrooms on the R class ships are a little on the snug side.
That said we love the product they provide and keep coming back to Oceania as our line of choice.