Is Single entry schengen visa ok?

[hllej0]

We're currently having single entry Schengen visa, and will take the Norwegian cruise visiting the following ports. I was getting mixed information on whether it is required to have a multiple entry visa to board the cruise. It is so closed to the trip, and it is very difficult to get visa appointments. We're traveling with babies and toddlers, and would be a disaster if can't board the cruise.  Anyone can help please. 

 

ROMA, ITALIA

LIVORNO FIRENZE PISA, ITALIA

NIZZA/MONACO (VILLEFRANCHE), FRANCIA

PROVENZA MARSIGLIA, FRANCIA

BARCELLONA, SPAGNA

PALMA MAIORCA, SPAGNA

IBIZA, SPAGNA

MALAGA GRANADA, SPAGNA

CADICE SIVIGLIA, SPAGNA

LISBONA, PORTOGALLO

[Twickenham]

Italy, France, Spain and Portugal are all within the Schengen area, so if that is your itinerary, you're good to go.