We have been to Washington many times over the years, I have been to the Pentagon (building, not memorial) a couple of times, but my family had never visited so we decided to try and get a tour (if you can call it that, more later).
From what I could find regular Pentagon tours need to be booked through the Pentagon website starting 6 months in advance. They book very quickly so you need to book 6 months in advance. Maybe there are other ways to get a tour (Congressman etc.), but this is all I could find. After booking you will need to send them a security roster of all attendees for your group. When they confirm your tour be sure to read all the security and ID requirements (you will need two forms of ID, one of which is a government photo ID). We found the booking and ID process simple, but you do need to follow all the steps or you will not be allowed on the tour. We also found the staff responsive to e-mails etc.
We would recommend arriving for your tour by the Metro, a few minutes from the Mall area on the Yellow or Blue Lines, easy no hassles. Be sure to arrive early to give time for the security process.
After the standard Washington security (this one was a bit more like airport screening than others) and ID check you are allowed to wait for your tour in a waiting area. Don't forget to check in at the tour window.
The tour of the pentagon can be disappointing to most if you do not know what to expect. You are escorted through halls that could be in any office building in the world looking at displays about the various services of the military. In the past the tours took you into the courtyard and by some of the offices of top commanders, but not now. As noted some may find this disappointing.
Highlights of the tour were going to the memorial at the location where the aircraft impacted the building on 9/11 and being in the building itself (we were at the Pentagon!) that was about it. We also did get to see General Macarthur’s Medal of Honor. After about 1 hour we were escorted back to the waiting area and on your way.
From what I could gather, most tours are done for school groups. Our tour was our group of 4 and a middle school group of 40 or so. The kids in the group acted, well like kids on the tour, so if you have a low tolerance for the activity of a large group of middle school kids, maybe this tour is not for you.
The tour is escorted by members of military of honor guard detachments. Our big disappointment of the day was the lack of professionalism these folks presented. They were so unprofessional in that they were laughing and joking about the terrorist attack on the building even when we were in the memorial area. Maybe they were too young at the time to understand and remember. I would have hoped for better from our military.
After the tour we went to the Pentagon 9/11 memorial outside (another review) the building before heading back into the city.
All in all for our group the value of the Pentagon tour was to just say you were there, not much else. If you have never been to the building before we recommend a visit, if you have been there before, maybe visit another sight.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.