Day trip to Monaco

Have you tried googling "things to see and do in Monaco" ?

We did a day trip to Monaco last fall. The tour of the Palace was pleasant. The park along the edge of the bluff near the palace is pretty. Other than that Monaco is a tourist trappy nothingburger.

The Royal Palace and the Cathedral where Princess Grace and Prince Rainier are buried.
It will not take all day.

Rick has good information in his guidebook for a day trip to Monaco including a self-guided walk. We took the easy public bus #100 from VilleFranche to Monaco and hiked up to the Palace Square to see the changing of the guard ceremony in front of the Prince's Palace with gorgeous views. Visited the Cathedral of Monaco where Princess Grace was married in 1956 and then buried in 1982. We enjoyed a nice seafood lunch at the harbor. Then up to the famous Monte Carlo casino for a look inside. It was a great day!

I think people have you covered with the above -- it's more of a checklist destination and won't take a full day without spending time at sites that might be best spent elsewhere. By all means go and hit the highlights mentioned, though.

Also the Jardin Exotique, the Rose Garden, the very nice Japanese Garden built on a car park, the sights and views of the Formula 1 corners, the three dimensional puzzle, and much more. It is all down to what you would like to see, and very easy to get around.

The Aquarium - with its Jacques Cousteau connections - is absolutely fabulous and perhaps the best in the entire world. I have spent most of a day there previously and only seen a fraction of the place.

go gambling at the casino

The only must see for me is the Oceanographic Museum.

Where are you staying? If in Nice, then take a bus. When we were there, it was 1 euro each way pp. See above tips for things to see and do. DO NOT take pictures in the casino. :) . Also, the casino has a dress code. Look it up and adhere to it before going.