Opinions on Lake Geneva, Brienz, Thun, or Luzerne boat trip

Where will you be staying while you are in Switzerland?
If it is a lakeside town with a boat service, then that is the obvious choice. Lake Geneva (lac Léman) is a big lake, mountains are in the distance. Vineyards along the northern (Swiss) shore.
Lake Brienz and Lake Thun (Brienzersee and Thunersee) are smaller and have mountains dropping into the lakeside. More "typically Swiss" towns along the banks.
I like Lake Lucerne (Vierwaldstättersee), it is larger than Brienzersee or Thunersee, with many side arms. And, the southern half (furthest from Luzern) is very fjord-like and mountainous.

Chris, thanks. We want to choose one based on scenery, not just proximity, so in light of that, which would you suggest?

" It sounds like Lake Geneva's mountains are more off in the distance, while Brienz and Thun's are very close. Is this an accurate way to put it? "

Lake Geneva is several hours from Wengen, so "off in the distance" is an understatement. Unless you're doing something else in the area, I wouldn't make the detour just to ride on that lake. However, if you do want to see Chateau de Chillon, Montreux, Vevey, Lausanne, etc, then a boat ride on Lake Geneva will be an easy "add on," as boats connect all these places.

Lake Brienz and Lake Thun are about 45 minutes from Wengen. Interlaken is literally in between these two lakes; from Wengen, you take the train (about 15 minutes) down to Lauterbrunnen, then change for the train (twice an hour taking 20 minutes) from Lauterbrunnen to Interlaken Ost (right at Lake Brienz). You can take a train, or a bus, or walk, from Interlaken Ost to Interlaken West, for Lake Thun (the walk is about 20 minutes).

I had a lovely boat ride on Lake Luzern, but I was staying in Luzern, and used to boat to get to Vitznau, where I then took a train up to Mt. Rigi. Again, I'm not sure it's worth a long detour if you're not going to be in Luzern otherwise.

Harold, when I made the comment about the mountains being off in the distance I did not mean in terms of Wengen to Lake Geneva. I meant in terms of how close the mountains are to each of the lakes as you are touring them.

Thanks for your suggestions as they are very helpful and will help in making a decision.

I've done boat trips on both Lake Geneva and Lake Thun and Thun wins easily in terms of scenery - both the mountains and the towns and villages along it. I was based in Interlaken and visited several of the towns along the lake by boat. Here are my photos of that. - https://andiamo.zenfolio.com/p205284896

Isabel, which towns did you stop on Lake Thun? I was thinking of stopping by a few on Lake Thun and Brienz aside from the obvious Thun, Spiez and Brienz but I haven't figured out which.

Thanks for clarifying. In that case, you'll love Lake Luzern, where you come close to mountains for much of the ride to Vitznau, due to the lake's irregular shape.

Oberhofen was really cute. Loved Thun and Speitz. Interlaken most people hate cause they just walk down the main street which is all touristy stuff, but there is a small but nice old town tucked behind that was really pretty nice.

Thanks Isabel. We'll actually base in Interlaken for logistics sake :) I'll add Oberhofen to our list.

And sorry for threadjacking, OP.

Love the photos Isabel. Thanks for sharing.

"Threadjacking". Love that term! Fun stuff.