Is that Oceana the ship or Oceana the Cruse line ?
If its P&Os Oceana then most of it is free cafe Jardin has a charge for diner as does the Horizon Grill...Taffy.
If it's Oceania then all are except for the select dining room. There may be a restriction on the number of visits to the Speciality ones.
I assume its P&O Oceana, in that case included in your fare are the main & self service restaurants for breakfast, lunch, afternoon tea, dinner and late night snacks. Also Cafe Jardin except during evening when there is a chargeable menu. If you mean by inclusive, alcoholic drinks are not included, nor are your tips which are Ł3.50 per person per day. Tea, coffee and biscuits are provided in your cabin. For a full list see p&O website.......https://ask.pocruises.com/help/PO/before-you-sail/fare_included..........Brian.