Pompeii vs Herculaneum

I would pick Pompeii. Herculaneum is mostly underground. You could do both in a long day. Not that far from Naples.

The two sites are quite different, I liked them both, and yes, certainly they can be visited in one day from Naples. Of course in summer the afternoons especially can be hot and crowded, and in winter darkness comes earlier. I visited both sites plus Villa Oplontis in one day from Sorrento, but it would be equally easy from Naples. I found the three sites to be a bit much and tiring in one day, in part because I found that even though Villa Oplontis was only about a 4 minute train ride from Pompeii, as I remember, there was a 2 hour gap in the train schedule on the Sunday I was doing this. Two bits of guidance: (1) it is good to visit the Archeology Museum in Naples on a day before you visit the ruins, as many of the works of art that will help you appreciate the ruins are located in the museum, and (2) I, and many others, recommend utilizing one of the human guides at Pompeii, as opposed to just a written or audio guide. A 2-hour guided tour is about €10, you gain a lot of information, and the guides never get lost in the ruins and know which areas are under repair and not accessible. There are generally many guides available at the entry, talk with a few and choose one whose personality you enjoy and whose English you can understand easily. I myself did not use a human guide and wish I had -- I was often lost and missed some important areas in Pompeii.

I'm not sure what Frank means by "underground." Pompeii is much larger and there is much more to see, but Herculaneum gives a better idea of what a town was like, so it's hard to choose. If you have the stamina, you could see both in one day. I went to the archaeology museum after visiting both (3 separate days). Had I been to the museum first, I would not have spent as much time at the sites looking at the art work.

I agree with Chani, Herculaneum is definitely above ground. You could do both in s long day, but be sure to see the archeological museum in Napoli as well.

You can most definitely see both Pompeii and Herculaneum in one day. Allow 4 hours for Pompeii, a break for lunch, and another 3-4 hours for Herculaneum. If you are going in the heat of summer take frequent breaks. Pompeii has a little cafeteria with air conditioning and food/drinks if you need to escape the heat.

Pompeii is larger, more "ruined" and has some unique features like the house of Veti, bathhouse, the Amphitheatre and the plaster casts of the Pompeii victims. I second what Larry said, I regret not having a human guide. The site is very extensive and can be very easy to miss the most interesting parts, even with their (lousy) map and audio guide. The Rick Steve's audio guide for Pompeii is decent, but still no substitute for a real guide in this case.

Herculaneum was buried in mud rather than ash. Because of this it was better preserved. It looks and feels more like a "real city" Some buildings have their original wooden doors and second /partial third story walls intact! Herculaneum is smaller and easier to understand without a guide. From what I understand from other travelers the audio guide for the site (just a few euros to rent) is quite good. You probably wouldn't need an actual human guide for this site.

As Rick points out in his book, both Pompeii and Herculaneum are only partly "uncovered". Any feeling of "completeness" in Herculaneum, or even the vast Pompeii is an illusion. Much more of Herculaneum can be assumed to be beneath the modern city around the excavation.

My personal feeling is that Pompeii is the better outing. But for a less-abled visitor, someone sensitive to the sun and the heat, Herculaneum has a little bit more shade. OTOH, it's a 15-minute urban walk from the Circumvesuviana station. Both sites have difficult walking conditions, with Roman paving stones, ditches, and erosion. Herculaneum has only vending machines for food and drink. You cannot re-enter either site if you go out to eat in a restaurant. The large cafe in Pompeii is air-conditioned and pleasant enough, in a mass-feeding kind of way. But the toilets suffer from over-use.

If you have been to other Roman excavations, it might not be necessary to see both. We went to both, and to Villa Oplontis, but there's a point of diminishing returns for anyone, especially families with children. If you've never been to an ancient city, I would certainly go to Pompeii.

Edit: Herculaneum vending machine only report is end of May, 2014. Can't say if they have more in a peak month like August. But there are no slow times at Herc and Pomp! Buying more water is the most important task in summer. You can also assume that a different 8% of each site will be closed for conservation each time you go.

Very doable in a day.
I'd go to Pompeii early, take water and a hat.
Herculaneum on the return, its down hill from the station. Much more compact.
I'd also take a cab back up the hill to the station.

What Frank probably means by "underground" is that Herculaneum is down in a huge pit that was excavated, so it's below ground level. This picture shows what I mean. Herculaneum - Uncovered city You can see the modern day town of Ercolano up at ground level, with buildings that come right to the edge of the pit. But you don't much notice that while you're there because the pit covers a very large area - about 700 feet by 500 feet. (Picture a 70 story skyscraper on its side for 700 feet.) Herculaneum takes about 3 hours to "do", imho. I would not do Pompeii on the same day, but then I like to take a fairly easy pace on my vacations.

Tim says Herculaneum has only vending machines, but we ate at a little outdoor cafe there when we went. Granted, it was 2003, so maybe the cafe is gone.

I have never been to Herculaneum, but did a trip from Rome to Pompeii two years ago. If you are staying in Naples it may be possible to see both in a day, but not if you are staying in Rome like I was. I think it really all depends on your level and interest in archaeology. My educational background is in archaeology so I spent the entire day at Pompeii and still perhaps only saw half of the site as it is very large. Others may look at it say much of it looks the same and browse right through it in a couple hours and move on to the other site and Naples Museum.

Not to overstate the case, I suspect that many visitors to Pompeii don't recognize or know that (for one example) the Faun at the Villa of the Faun is a replica, and that the original is in Naples. Likewise, people queue up at the Pompeii brothel, but unless they got into the ... er .... spicy ... room at the museum, they don't know that the frescoes are replicas. While we looked at the entire Archaeology Museum in Naples, I will most remember the Farnese Marbles, because of their huge influence on Renaissance art (and even today - Jeff Koons (blecch))