Advice re: visiting Monastery Jeronimos and Sao Jorge castle

We visited both the last week of September last year. We easily walked up with no lines to the Sao Jorge Castle on a weekday afternoon. It's a nice wander with great views. I don't recall any must-sees, but I also think it may take longer than an hour because it's a large area. Be prepared for a steep uphill walk to get to the castle. There is likely a tram or bus that would have got us near, but we took our time wandering through the Alfama and Mouraria neighbourhoods below the castle.

On a different weekday, in the pouring rain we arrived in Belem at about 10:00 and after a 10 minute walk from the train station, a sign for the monastery said the waiting line was 2 hours long. We also counted 28 tour buses in the parking lot. We made the executive decision to wait until late in the day. We came back about 4:00 and walked right up to the ticket office and went straight to a line that took about 15 minutes to get in. There was no signage and so we had no idea we were in the line for entry into the free cathedral. We didn’t realize there was a 2nd entry further down for the monastery. For that we walked right in. We had so many people tell us the monastery was a must-see, but I thought it was underwhelming and a disappointment. The cloisters were beautiful, but nothing earth shattering that we haven’t seen before. For us, it would have been a waste of time if we had stood in line for 2 hours.

It's interesting how everyone's tastes and impressions can differ.

The Jeronimos Monastery was one of my favourite sights in Lisbon. I loved all the beautiful and intricate details on the pillars and arches, as well as the tiles in the dining area.

It was easy to combine with visits to the Belem Tower and the Colonizers' (Discoveries) Monument. We walked from those sights to the monastery, and saw a really cool piece of wall art (a raccoon made of junk) on the way.

We stayed in the castelo district, just a couple of streets over from the inner walls. What I remember most about the castelo are the lovely views from the walls, the peacocks (some of which would spend time outside our kitchen window), the cats in the "moat," and the towers we could climb into. I'd say we spent more than an hour, but not more than two.

We had Lisboa Cards, and they included admission to all the above, as well as other sites and transportation throughout Lisbon and to Sintra and Cascais. Not all city cards are worth it, but we thought this one was. https://www.visitlisboa.com/en/p/lisboa-card

There are two separate lines for the monastery and the church because they do not connect. The church closes between 12 and 2 and does not open until 10.

I was there twice and like Allan left the first time because of the lines. I agree late in the afternoon is your best bet. We went about 3 to the church and then to the monastery. We had tickets for 4 but were let in early.

Thank you all for your words of wisdom.
It sounds like somewhat mixed/positive reviews on the two sights, although all agree that afternoon visits should be okay without tickets?
Appreciate you all-Jane

To get up to the castle there is an elevator in a building that cuts off quite a bit of the climb. If you google elevador castelo you should find directions. It was in the same building as a supermarket when we were there years ago. We also stayed up in Castelo and enjoyed the views from the Castle.

We had some challenges getting to Belem, and this was years ago and April. Most of the trams etc were packed and it took some time to get there. I think we ended up taking the train to Cascais and it stopped there as well. As well, it can feel very hot waiting in line with all the white tile and no shade. I personally might try for the morning, or maybe later in the afternoon