Is it feasible to visit Murano and Burano in a single day?

Yes, vaporetto No 12 from Fond. Nove will take you there.

Yes. We did it

I would go to Torcello too.

If all you have planned for a single day is Murano and Burano then you quite possibly will have a LOT of extra time on your hands.

We’ve done the three islands — Murano, Burano, Torcello — at least three times as a day trip. We usually leave from Fondamente Nova about 9AM and stop first at Murano, then following the Rick Steves’ self-guided tour in his book, proceed to Burano where we have lunch which we then walk off (a bit) on Torcello. Last visit we got off at Mazzorbo, which is a short walk from Burano and is attached to Burano by a bridge, and ate at the very good restaurant there. It is a bit of long vaporetto ride back from Burano but we are back between 3 and 4PM.

In addition to Murano and Burano I would also recommend Torcello. We especially enjoyed visiting the Cathedral of Santa Maria Assunta. Their audio guide was very helpful for viewing the amazing mosaics. The mosaics date back to the 11th and 12th century. All Byzantine style. Well worth the stop.

Like the others, I say easily the two islands, certainly also Torcello, and even also Mazzorbo in a day. Of course how long it takes depends on your pace. I find both Murano and Burano are more interesting if you wander beyond the touristy commercial areas. Some of the “private showrooms” of the Murano glass stores have very creative and beautiful larger glass pieces, if you ask and can get invited in, by looking interested, and likely without small children. On Burano, certainly stroll through the small neighborhoods with canals and pastel colored houses. Traditionally panted that way, so fishermen could look toward home and know which home was theirs. There are two or three well-known seafood restaurants on Burano, for lunch or even dinner. Famous dish there is risotto di pesce, which sometimes takes extra time and may require at least two people to order it. On Torcello, it is about an 8 minute stroll from the vaporetto stop to the church complex, which is the birthplace of Venice. When I was there, there was only a combo ticket for the three buildings there, one being the bell tower, so give yourself up to an hour there to visit all three and justify the price of the ticket (which I remember was 9 or 10 euros back in 2014). If you have lunch, and don’t linger, you can be back in Venice well before dark. Although once I stayed for dinner, and then was the only passenger on the last vaporetto back to Venice. That was also the only time I was asked to show my pass while riding a vaporetto, I must have appeared to be a deadbeat. The back streets of Venice were sure dark and lonely for my walk back to my hotel.

You can of course get lucky. Mazzorbetto is the island opposite Mazzorbo, and the vap does not call there. The Mazzorbetto fort is now used by a boy scout group, they were doing tours and offering lunch when we were there.
The fort never fired a shot in anger, being located in such a way as to only be useful should Venice open hostilities with Torcello.

I went to the cemetary island, then Murano, last May. I had intended to visit Burano too, but I really liked Murano and decided to linger there. I think with an early start and without lingering, you could easily visit both Islands in a day.

Another yes! For us, we preferred Burano to Murano😁

If I remember correctly, a 1-day vaporetto pass costs less than individual tickets for this trip. If you plan to buy a multi-day vaporetto pass for your stay in Venice, then this trip would be covered by it.

Yes, we did it easily.

Easy to do. Liked Burbank and Torcello much more than Murano.

Just seconding vftravels's recommendation of San Michele, the cemetery island. It's on the way to Murano, but only one Murano-bound line stops there. It's very lightly visited, which is a nice contrast to both Venice proper and Murano. If it's sunny, though, be sure to bring an umbrella for shade - the gravestones are not shaded.

Hmmmm, Suki likes Burbank more than Murano, now that’s a stretch. Surely Murano is better than that!

I've done Murano, Burano, and Torcello in a single day. No problem.
Though our last time in Venice, we spent so much time on Murano that we didn't have time to get to the others.
If you're moving through with a casual interest, you can definitely get through all in one day. If you're doing any serious shopping, it could take much longer than expected.