I'm unsure of when I want to visit the Pantheon, and I want to keep that at least somewhat flexible. Is there any risk of tickets selling out or can I just buy a ticket on my phone and walk over to go in?
I am wondering the same thing. I am staying near the Pantheon this week and was unsure when I want to visit it. We are so close and will be in Rome for four days so I'm sure we can find sometime that will work. We're leaving today. I will let you know how easy it is in a couple of days.
No it doesn't they control the flow of the crowd at the entrance so it is at a safe level. Just avoid arriving between 10 am and 2 pm.
https://portale.museiitaliani.it/b2c/buyTicketless/33f77159-0acd-40c4-8524-701f33aae108
Don't buy in advance, there are some scams out there. This past summer 2024, we simply walked up and paid in euros (get in the line to the left of the entrance). The line for people using credit cards was very long -- over an hour wait in the sun, whereas if you pay in cash, there is usually no line or just a 5-10 minute wait.