Possibly the worst airport I've ever flown through and that's saying a lot, given the decrepit…read morestate of some American hubs. Lisbon took a good chunk of my soul. A few recommendations:
1. Budget more time than you think you'll need if you have an international flight (non-Schengen) AND you have a non-EU passport, which is the majority of travelers. Sure, you may feel a little silly sitting at your gate but that beats waiting in the middle of an enormous line knowing that your flight is leaving without you. A toss-up as to whether the airport staff (see #4 below) will try to help you out.
2. The layout is so poorly organized, it's almost comical. It's like if someone was handed the task of designing an airport to maximize traveler confusion and stress, and received an A on the assignment. So - first you go through security, where they check your passport. You might assume you're good once you see a maze of duty-free shops and restaurants but oh no, you're in for a nasty surprise. Do NOT waste any time getting stuff here. Keep walking and you'll eventually stumble into a massive queue for passport control. You pass under an arch and you're hit with more waiting. When I was flying out in June, they were rolling out the EES biometric system but, for the passport control that I endured, they were just clearing people manually because the machines were glitching out.
3. You've made it through after hours of standing in a sea of other complaining, dead-eyed visitors for whom the past few days of sunny beaches, delicious sardines, and stunning landscapes are now a very, very distant memory. You search for a restroom or maybe a cafe to grab a snack before boarding or, heck, even the Wi-Fi page to send an overly detailed complaint to the group chat.
NOPE. You're going to wait in more lines for the women's bathroom, to get coffee/food at the skimpy tiny cafes servicing the post-passport control hordes, and you're going to stare in disbelief at the broken Wi-Fi link.
It's crazy. The infrastructure, both physical and digital, for this airport is from something decades ago. Utterly absurd and embarrassing.
4. To make matters worse, we managed to locate our gate but missed the very, very tiny sign for it pointing away from a SECOND round of passport control. We were standing in line, looking at our gate number only a few feet away, when some people in front of us finally flagged down an employee and they were able to corral us to the right spot. As we waited for our gate to open, we saw a few other people in the same situation including two poor souls who had gone through passport control twice. We asked one employee if she or someone else could make a general announcement to the queue that passengers on "TPXXX flight to Boston" did not have to stand in this monstrous line and she basically shrugged her shoulders, saying that people had eyeballs and needed to pay attention to the (abominable) signage. People like us who missed it.
5. Budget an additional hour or two if you're thinking of claiming VAT refund status.
6. There are two lounges, ANA and TAP. You need to get through passport control to access TAP. ANA's entrance is located before passport control but when we lined up to get in, the staff at the door pointed us to passport control. When we finally made it through and then tried to find the ANA lounge, the TAP people told us it was before immigration. A mystery for another day, I suppose.
7. Don't even get me started on the utter pandemonium that was (1) trying to locate the car rental return and (2) actually trying to return it.
Overall - yes, Lisbon's airport is as bad as all the stories say. Try to save yourself from some high blood pressure and fly out of Porto instead.