Best Hotels in Lausanne and Lucerne

Best is a relative term. There is a Marriott Renaissance 5 minutes from the train station in Lucerne. It is very nice.

Hotel des Alpes in Lucerne also gets a lot of mentions here.
As for Lausanne, Château d'Ouchy is pretty good, expensive but not eye-wateringly so, and right by the lake. This being said, I would rather stay in Vevey, which has a couple of upscale hotels by the lake. Or for something simpler, Auberge de Rivaz right in the Lavaux vineyards (I only know the restaurant, which is good, but the hotel looks nice too - despite being next to the road and the railway)

Best is really subjective. We have not yet stayed in Luzern, but when we were planning to, the hotels I favored were Hotel des Alpes and Hotel des Balances. Both are across the famous Kapellbrücke (pedestrian bridge) from the train station.

There are hotels on the same side of the river as the station, if you prefer, and some are very close. Hotel Ameron Flora and Hotel Continental Park are probably the closest—-like within a block or so of the front. If you go out the side exit, Cascada Boutique Hotel is very close. But Inhave no experience with any of these so cannot make a recommendation.

I just stayed at the Marriot in Lucerne and as threadwear mentioned, it is very close and convenient to the train station. There is a nice park a block away and it’s just a quick walk over a bridge to the old town area. The rooms and staff were great, but it is expensive. I stayed there because my travel companions had some credit card points to use.

I am returning to Switzerland next June and decided to try the hotel des alpes that balso mentioned. As much as I liked the Marriott, when I looked at rooms for June, it was just a little more than I wanted to spend. I had heard hotel des alpes mentioned here many times and so I booked there instead. It’s a little further from the train station, but it’s not too far once you walk over the bridge.

I can’t help with Lausanne as I decided to stay in Montreux instead in June after watching this video. The Grand Suisse hotel is just steps from the train station.

https://www.youtube.com/watch?v=hAT3YVfhQ4g

If you need a hotel for Basel, I just stayed there too and stayed at Hotel Schweizerhof. Fabulous hotel and staff and super convenient to the train station.

I stayed at the Hotel des Alpes in Luzern in August 2019. The location is fabulous. It is a short walk across a bridge from the train station. The hotel overlooks the river and the Chapel Bridge. It's restaurant borders the river walkway. I had a balcony room with an extremely small balcony. I wouldn't worry about the balcony, but I would make sure I had a room with the river view.
There was no air conditioning at that time but I am not sure that this will be a big issue for you in May. The hotel did provide fans in the rooms that worked fairly well on the hot days. The room was clean and quiet.

The restaurant at the hotel was excellent and there is an entire shopping mall under the train station where you can buy snacks, groceries and other meals. A dept store with a rooftop cafeteria is also a short walk away.

The front desk was able to give very helpful advice about sightseeing in the area as well as sold me the "golden ticket" for the Mt. Pilatus exploration. I took a bus from about 100 feet from the hotel entrance to the area where the cable cars go up. It was about a 3 block walk to that station. The cable cars took me to the top of Mt. Pilatus. When it was time to return, I took the cogwheel train down the other side where it connects with a Lake Steamer for a scenic ride back to the dock in front of the train station. This was a great day trip and the convenience of the ticket and directions from the hotel were very nice. It was also an easy walk to the Lion of Luzern, the ramparts above the city, and the lakeshore.

I think this hotel is worth any "splurge" factor.

We stayed at Hotel des Alpes based on the recommendation from this forum. Breakfast used to be included, but not anymore. The location is fantastic. Yes, opposite side of the river from the train station, but a very easy and short walk, and adjacent to the Chapel Bridge. Very walkable to restaurants and a stroll along Lake Lucerne as well as the Lion Monument.
We booked a room with a balcony, which we appreciated because the rooms are quite small (not much room for large suitcases) + a couple mornings our breakfast consisted of Starbucks coffee and their breakfast sandwich, which we brought back and ate on the balcony.

The best hotel in Luzern is probably the Grand National Hotel Luzerne. Five stars

In Lausanne, try the Beau Rivage Palace. Also five stars.

Per Nite will run between 350 and 450 Swiss Francs.

I haven't stayed in either.

If you want to stay on the lake in Lausanne, it depends on your budget. The Mövenpick is a nice 4* standard hotel more or less next to the metro stop - they have good-sized, recently renovated rooms and many have lake views. A bit higher up the price range and with more character, look at the Chateau d'Ouchy or the Angleterre; for a big splurge, Beau Rivage Palace. All are convenient to the departure point for lake cruises as well as the Metro (free with visitor card from your hotel - it will take you to/from the main train station and the city itself, handy since the city goes steeply uphill from the lakeside).