ideas for killing time between early arrival and access to Airbnb check in?

Just a thought, a pricey one! Could you see if you could rent a hotel room near your Airbnb for an early morning check-in with a 3PM checkout? Maybe some hotel would be willing to work with you on that. Perhaps your Airbnb host would have a suggestion/recommendation as well.

@pmilholland10 - You can use a luggage storage service such as these - https://luggagehero.com/lisbon/ and www.stasher.com and be sure to book a Lisbon food tour to kill time before you check in at your Airbnb. You can also book a hop-on-hop-off bus or tuk-tuk tour to see the city's main sights while resting. Are you open to this?

Assuming the weather is nice, take an Uber or Bolt to a luggage storage place as the previous post mentioned, then just wander for a while, in the central Baixa, maybe take the tram or bus out to Belem for riverside walk and a look at some of the sights. Anywhere you could stop at a cafe for a pastry and coffee, sometime noonish or shortly after, head back toward central Lisbon and go to the Time Out Market, browse the food stands and have a light lunch (or more), about that time you will need to pick up your bags and head to your apartment.

All that offers plenty of fresh air and sunshine, light amounts of food and caffeine, a glass of wine or a spritz at the market won't hurt you.

All that assumes you are staying somewhere around central Lisbon, so depending on that, there may be other options.

those are all great ideas that we will consider. I think ditching the bags for the day and just see the sights would be good. I was thinking we could go for breakfast somewhere in Lisbon after we arrive but that would keep us occupied until 10:00AM. We could go to a museum but that might put me to sleep -:) Anyone know of recommendations for a good breakfast place that's open at 07:00 either in a section of Lisbon or on the way?

Staying outdoors in the daylight would be much better than trying to stay awake in a museum on arrival day. I haven't been to Lisbon recently enough to make a specific suggestion, but Lisbon has multiple interesting neighborhoods for casual wandering.

Paul has some excellent ideas to get out in the natural light by going to Belem and walk along the waterfront, get your first taste of Pasteis de nata, see the Monument to the Discoverers and perhaps the Belem Tower. For lunch, the Time Out Market is very near the Metro station Cais do Sodre. You will take the Metro from Cais do Sodre station to get to Belem. Here are links to the famous bakery for Pasteis de nata and for the TimeOut Market

https://pasteisdebelem.pt/en/

https://www.timeout.com/time-out-market-lisboa

We decided to go the locker route and drop off our bags near our Airbnb near Baixa, then wander the streets for a while. Thanks for the advice about Belem that sounds like a great idea!

Eyewitness Guides Lisbon Like a Local book has a nice walk of miradouros that could be a good way to pass the time. There are many places along the way to stop for a coffee and pastel de nata.

Agree that 5:30 AM arrival makes for a long wait to check in. Your experience will be affected by how well you sleep on the plane, what class you are flying and how long your travel day has been. Flying business class directly from NYC vs coach from Seattle with a layover in Boston makes a big difference in whether or not you can power through your arrival day until 3 PM. Once upon a time I could. I don't anymore.

tried to book our stay one day earlier

Even though you are doing the store your bag route, I agree with booking a hotel. Agree that getting out and walking is the best cure for jet lag. And, a one hour nap, change of clothes and a shower is a great addition to that walk.

I would do a free walking tour, they usually begin about 10:00 or 10:30 and take about 2.5 to 3 hours. Something easy to do when tired.

I have arrived very early in a number of cities (not Lisbon) and after dropping luggage off, I try to find a walking tour. It takes the pressure off of me to try to navigate through a city when I am jet lagged. In addition to the free walking tours that others recommended, you might want to check out the Eating Europe Best of Lisbon Tuk Tuk tour. It starts at 10:00 a.m. and is 4 hours. You ride a tuk tuk to see all the sites and then eat at some amazing local places to eat. If I recall, you end the tour in Baixa.

Two places I can recommend to eat, that aren't terribly expensive are: Augusta, fabulous avocado toast and everything is homemade. There is one location in the Alfama and the other in Belem just a short walk off the main road. It is near one of the main train stops I believe the one you get off for the Coach Museum. I think there is an Honest Greens in the Baixa area. They are a chain and in many locations, just Google.