Sardinia and Puglia

In Cagliari there should be no issue year round—were you going to stay in smaller towns on the southern coast? I think the beach weather could likely be good longer than the clubs would be open. Hopefully you’ll find some feedback on the specific time frame.
If you want to get your beach fix in Puglia, the beaches north of Gallipoli fit that description. Ironically, I enjoyed the cultural aspects of Sardinia more and the beaches of Puglia more, but a lot of that could be the timing (May, when the seas are so chilly but the hiking weather is divine)!

I have been to Sardinia in mid/late September. We visited the last week of summer (2022) and the weather was definitely starting to turn by the end- we had perfect weather most of the trip but the penultimate day it was too cold to go into the water- I was sat on the beach in a jumper- and the final day it rained the whole day. In that case to be safe I would visit Sardinia first- the earlier you go the more likely you are to have nice weather. If it gives you an indication, a lot of the seasonal flights to Corsica and Sardinia stop at the end of September. For white sand beaches, the very best ones in Sardinia are in the Maddalena Islands. You can stay on the islands or visit them by boat easily from Santa Teresa di Gallura. I've not been to Puglia so can't offer any advice there.

I've never been to Sardinia in September or October (always in June or July), but my preference would be to go as early as possible in September, because the most beautiful feature of Sardinia is the amazing beaches and water, and you may not be able to enjoy those in October as the weather in the island in October may be iffy by then.

Therefore in your shoes I would start your trip from Sardinia, then go to Puglia later, since Puglia has a lot to see in terms of history and architecture even if it's no longer beach weather (although their beaches can be great too). Beach clubs will be largely closed in October, and even as early as late September.

In Sardinia I've been only in the northern part. Santa Teresa di Gallura is my preferred base, especially because of the vicinity of the Maddalena Archipelago, which I recommend to visit on a boat excursion. Those boats don't operate in case of imperfect (even just windy) weather, so that is another reason to visit Sardinia early. You'll need a car in Sardinia, and most roads along the coast are curvy highways, so travel times are long even those things may look close on a map.

I would suggest you flip the order of your itinerary and hit Sardinia first, followed by Puglia.

We went to Sardinia in the fall of 2024, arriving on Oct. 1 and learned the hard way that the beach clubs (lidos) almost all close on Sept. 30! We stayed in Santa Teresa in the north for about 4-5 nights, and another 4-5 nights in Santa Margherita di Pula in the south, and can’t really recommend either of the hotels we stayed in, although both parts of Sardinia are worth staying in and have nice beaches nearby. Cagliari is also a lovely city to explore for a day.

Unfortunately that fall was unbelievably rainy- of our approx 35 days in Italy and Switzerland, including Sardinia, Volterra and Rome, it rained about 32 of them. A fluke, I’m sure. But the weather and the availability of prime beach facilities definitely declines in Sardinia once you’re into October, at least in our limited experience, and the season really seems to end pretty abruptly.

We’ve been to Puglia twice, most recently this fall (Sept. 21- October 6 or so), and about the same time in 2022, and have based ourselves both times in Locorotondo and Lecce. This time we flew into Rome and then trained to Bari for 3 nights, which we enjoyed a lot (although not for beaches). Our hotel choices prob wouldn’t be yours; we stayed in a funky place in Bari, an agriturismo we loved in Locorotondo (Masseria Aprile) on our first visit and a “villa” we loved less on this year’s trip, and a B & B we like in Lecce (B & B Centro Storico). We had perfect weather the entire time this fall.

I assume you will have a car. Get the smallest you can manage! There are indeed many small towns worth exploring in Puglia, and you can explore a couple per day if you’re energetic. I will say that we found the tourist crowds to be quite large this year in Puglia- fall is no longer the off-season and Puglia is no longer undiscovered. Some American tourists but also lots of Europeans.

It’s tricky to manage your timing to these destinations. Sardinia seems to be hopping before early to mid September, with good weather and everything open- but that’s when it’s the most crowded. Good luck sorting out the best plan for yourself.

Neither.

Been to both, both in September to early October (separate trips). Absolutely loved both, both are favorite places, among the best trips I’ve done.

My advice is to not try to combine (squeeze) these two large and spectacular regions into a single, too-short trip. Each alone deserves more time than you are allocating to both combined. These would be better done as two separate, three-week trips (and even with 3 weeks in each, you still would have to make hard choices over what to include or cut).

Wonderful places with lots to see and do.