*Solo* 12 Night Mediterranean Cruise - 1 Adult Full Board P&O Iona 2nd Jan 2023 , Inside Stateroom (From Southampton) = £570 @ SeaScanner

There is a drinks package for £39.95 a day per person. It's quite limited.
We have just come back from a Britannia cruise and have now booked a Christmas cruise on Arcadia. The bar prices are pretty reasonable (not wetherspoons but similar to other pub prices). Lager was just under a fiver a pint as was cider. 500ml of Doom Bar was £4.70. basic cocktails were £6.95. Bottles of wine in the restaurant started at about £18 and there was a perfectly acceptable Chardonnay for £22.
Compared to other cruise lines the P&O prices were pretty reasonable (edited)

Most cruises let you take a fixed amount of alcohol on board when you’re first embarking. I’ve always taken more than the allowance in my case. Never had issues yet. It will be confiscated if you bring it aboard when you when you are embarking between stops and returned at the end of the cruise. Solo is very common. You’ll be overrun with companionship, especially at dinner time. You’re unlikely to sit with the same person(s) twice, only because you won’t see them. Go for it. (edited)

So did I, the food was fine in the restaurants if you could get a booking in, we did, many didn't, the entertainment was pretty poor and there was not a great deal going on.
That dome which looks great is acoustically dead.
Most people end up in the "Zoo" (Horizon buffet on deck 16), that was awful, an absolute free for all.
They call it freedom dining however that is incorrect, you struggle to get what you want despite the restaurants being half empty because they simply don't have enough staff to open all the tables when the ship is full.
Add £39.95 per day for the adult drinks package and another £40 per day for the adults only section if you don't want kids running around and that "cheap" holiday suddenly gets rather more expensive.
Also be aware that everyone in a room needs to buy a drinks package or you cannot have one.

I relish the stops to be honest. The ships are huge. 2 full days at sea is excellent as you get to experience what the ship has to offer, spa, shows, cinema, wine tasting and general exploring as the shop is huge. Also you get to sit down with a book and a glass of wine. When you do back to back stops it’s pretty exhausting, for me anyway. You’re normally disembarking at around 8am then back on board at say 4pm. If you’re in a hot country you want to shower and all the rest, so down time is good.

Drinks on P&O cruises.
The "Ultimate Drinks Package" covers many alcohols including spirits, some cocktails, wines, forified wines, prosecco, beers, ales Costa coffees, teas. draught soft drinks , bottled water etc. (think the max price per drink may not exceed £6.95... so not everything available)
This package will set each passenger back £40 per day currently, and can be bought onboard no later than the day after boarding and must then cover the entire duration of the trip. If there are 2 people sharing a cabin, then BOTH are mandated to take the same package (unless one has a medical cert to prove no alcohol allowed). Two of us were on Iona in September for the 14 day cruise around Med. Our 13 day drinks package set us back just shy of £1040... so only good value if you really can put them away!
Having said that, this package is in practice unlimited (officially there is a max of 15 drinks per day, but this is ignored, provided you can walk properly and do not have a tendency to go Yob. Spirits can only be served in single measures (officially anyway), but you can keep them coming within a 15 min space of earlier ordering. Not everything available, but does allow for many high end brands e.g. Glenmorangie 10y.o. single malt etc.
Juices and disgusting coffee is served with your breakfast (thank you for Costa alternative)
There are also non-alcoholic packages available (£20 p.d.)

Carry On Alcohol.
We each took on board 2 litres of whisky bought in Gibraltar (properly priced duty free). Although all bags are scanned at each boarding, we were not pulled up. Were purchasing to bring back to UK anyway.

We dined regularly with a couple that ALWAYS brings onboard a full separate suitcase full of assorted alcoholic drinks... NO questions asked or challenged (Officially only 1 litre allowed when first boarding). (Most cabins have a mini fridge.) HOWEVER, there MAY be a caveat in relation to this couple... Would you give a hard time to those that do 3-4 cruises annually with you?
PS The Med is miserable in January, so you will be spending all your time indoors or in a hot tub with plastic glasses f.y.i.

I’ve been on the Iona on my own this year and there is plenty to do and explore on your own or if you wanted to meet up with other solo travellers they do an organised meet up in the daily planner. (edited)

Drive there

Surface temps. vary a bit. They fall to as low as 5 °C (41 °F) in the extreme north of the Adriatic in February. Highest temps. are found off the coast of Libya, in August, where you can expect to water ski off the back of the ship on 31 °C (88 °F) waters.

But you wanted to know about in not on. I'm not sure how deep you were planning on going but it's a fairly constant 12.9 °C (55.2 °F) at 900 metres (3,000 feet) deep, and 13.1 °C (55.6 °F) at 2,500 metres (8,200 feet) deep, all year round. So, if I were you, I'd forget about a splash-about in the sea and just stick to one of the heated onboard pools (edited)

Which line gave you the extra onboard credit?

We didn’t spend a penny on board

Blimey, you must have a massive bladder to wait that long for the port stops.

Yeah the bay can be interesting! We've crossed it a few times on cruise ships and, mostly, we didn't notice it. One journey we had noticeable movement.
My sister has just returned from a cruise to the canaries and the ship diverted around the bay as the weather was rough. Unfortunately this meant that the visit to Tenerife was cancelled as it took much longer than simply crossing the bay.

4 days straight off at sea is unusual - normally you would get a stop in northern Spain or Portugal to break that up but, personally, I enjoy the sea days as they are the relaxing ones so this wouldn't put me off. Of course, everyone is different

How much value is a balcony overall. Never been on a cruise so interested to know what sort of price to put on a balcony view.
Is it worth £100 more, £500 more?

Yes you can bring a bottle of wine per person packed in your main luggage. I brought a bottle of spirits one cruise but could never find enough mixers. P&O are not as strict as some in checking. I have bought alcohol at ports of call and they didnt take it from me after scanning me through on return. Thats not a given though. (edited)

Most cruise ships/lines have these sorts of negative reviews Royal Caribbean and many others at 3x the price.

You have to remember this one alone ship can hold 5000 on one sailing.
99% of people that leave reviews will only review to complain and you never hear from them when they have an ok/good experience, so it's a completely skewed statistic.

If you book one £570 inside cabin, and one £665 balcony, this works out cheper than booking 2 people in one balcony cabin. They both have a double beds so you have a spare room for less money.

If you select the cheap saver fare - zero. For solo tracellers (choosing balcony) if you spend an extra £300 on Select fare -you get £220 to £280 on board spending depending on whether you take up free parking or coach fravel. This upgrade cost is less for a cheaper room but on board spend is also less. The P and O website gives a bit more detail. pocruises.com/fin…301
ps if you are parking your car at Southhampton - longterm parking is £140 so if you are getting a standard inside room its probably well worth the extra £170 to upgrade to select fare and get £135 on board credit as well. (edited)

It looks to be like you can book the room for just one person for that price

I've also booked this. First ever cruise. Solo traveler, but I'm 50. I'm hoping there will be ways to meet fellow solo travelers on board.

It depends on cabin and chosen dates, showing at £570 for me (edited)

No. Fine for me. Give me your credit card details and I'll book us a solo each (edited)

It's not school holidays so I wouldn't expect many kids.

You would have to look at the deck layout to be sure but usually the cheaper cabins are in less desirable places on a ship, maybe towards the front or higher up where movement can be greater than midships. Could also be due to being above a nightclub or below a restaurant. There are a number of reasons why some cabins are cheaper than others but a lot of it is down to location and the difficulty in shifting those particular cabins

Thanks for sharing.

Likely to be half empty ship with a 2nd Jan sailing...I hope 😁