Winter sun with 3yr old & 10 month old

February + short flight + good weather is challenging. Do you consider 4 hours short? If so, canaries are an option.

If not, or you don't fancy the canaries, I would wait until May/June and go to Spain (Nerja area?) or Greece.

Yes Canaries is the obvious answer for February. Though it will be spring rather than summer weather iyswim.

Sensatori Tenerife or Roca Nivaria (also Tenerife) both have kids club and creche if you fancied a few child free hours.

There are more with kids clubs from 3 but no creche. For example, Princesa Yaiza on Lanzarote, Sheraton La Caleta or Bahia del Duque.

May/June far more options - southern Europe is great then. Greece is lovely with kids IMO.

We went to Lanzarote one February half term and it wasn't warm enough to swim.

And the evenings were decidedly chilly. We needed the heating on in our apartment.

Make sure that at least one pool is heated and/ or indoors. If AI before you book call the hotel and find out when dinners starts in Feb- friends went out of season and dinner didn't start till 7.30pn- they had to take their dc out for food earlier as they could last until then. Nearly ruined their holiday as the evenings turned into a huge hassle.