The questions asked on this site are to all readers of this site, not nz.cruise.co. You would need to look at the brochure of whichever cruise company you would like to go with. In the back there is a description of the rooms, room sizes and on which decks 4 berths are available. We travelled with Ocean Village 2 last year with two teenagers. The outside 4-berth cabin we occupied was quite spacious compared to other companies. Royal Caribbean have quite large cabins for 4 with a seating area, but the sofa doubles as the 2 extra beds and my teenage daughter and son would definitely not share. Hope this helps.