Cascais & the surrounding areas have so much to do, but here is my top 10 plus a bonus.

1. Explore options of the water, like a sunset boat cruise from Cascais marina. Get there early as there's lots of shops, places to grab a coffee, snack, or drink, and take in the old naval battery that they've incorporated into the marina. Or come scuba dive with me for a half day trip!

2. Check out Casa da Guia, an indoor/outdoor market right on the water that has amazing views and is a good place to pick up a Portuguese keepsake if you're into that kind of thing. Casa da Guia also has my personal favorite breakfast cafe - we ended up going there almost every morning when we visited

3. Rent bikes or mopeds and cruise along the coastline, or through the city center

4. Visit Cascais city center, just beyond Cascais marina. My favorite stop for coffee, Fabrica Coffee Roasters, is there along with tons of other places to get a nice waterside view. Good overlook of the marina / battery, watch people play foot volley (volleyball with your feet?), THE ONLY MCDONALDS IN TOWN, more souvenir shopping, tons of things.

5. Rent a car or Uber and take a 20ish minute drive to Sintra. All sorts of historic castles that you can walk inside, view from the outside, or tour around the surrounding gardens at Pena palace. If you wanted to see everything at Pena palace alone, I would give yourself 3-4 hours. You can also see 2 other castles within an easy walk from the gates of Pena Palace.

6. Rent a car and take a day trip to Porto. We didn't do this on our trial trip, but it has a lot of attractions and the drive from Cascais to Porto is basically all along the water. If you're going to do this one, would recommend doing an overnight trip as it's a 3 hour drive.

7. Go and see Cabo da Roca - the westernmost point in Europe and deemed by Mike as "the cliffs of Moher of Portugal". Awesome views, easy hikes to viewpoints. DO NOT try to bike there. We made that mistake; it's not fun. You can get an Uber from Cascais to there for ~10 euros.

8. Find a beach to hang out - Praia da Duquesa close to city center and Guincho beach 2-3 miles out of town.

9. Take a surf lesson at Guincho beach

10. Rent some clubs and play a round of golf steps away from our wedding venue at Oitavos Dunes or Quinta da Marinha Golf resorts

11. Amazing food options. Reach out to me if you want specifics - tons of good seafood options especially.

Overall.... if I had one day of free time in Cascais and wanted the most "bang for my buck" I would:

1. Go to Casa da Guia for waterside breakfast at the cafe.

2. Rent a car or take an uber (probably easiest unless you already have a rental car) to Sintra. Tour the castles until early afternoon and grab lunch while there.

3. Head to Cabo da Roca to take in the sights and stay until close to sunset - amazing place to take that in.

4. Before the sun fully sets, head to Bar do Guincho and watch the sunset as you have dinner.

If you want a day where you aren't running around the whole time, going to the Cascais city center and relaxing on the beach would also be a great day.

Hope this helps, and in general you shouldn't have a hard time finding plenty of things to enjoy while you're in Portugal!

-Mike