Trieste Travel Forum

Is it necessary to buy a train ticket in advance for a particular departure from Trieste, or can one simply buy the ticket on arrival at the station? I want to take a 10:47 departure, but I'm not sure I will arrive at the station in time for that train.

You can just buy your ticket at the station, from the ticket window or a ticket vending machine.
I've travelled through Trieste on two occasions. The first time was when returning home (Switzerland) from Pula. I arrived on the bus in Trieste, and just bought a ticket to Bern there.
The second time I was travelling back from Split. I'd taken the night train to Zagreb. and IC to Ljubljana, a train to Villa Opicina, a Bus, then train from Trieste to Bern again. I bought a ticket to Ljubljana in Split, a ticket to Trieste in Ljubljana, and a ticket to Bern in Trieste. I still made it back in Switzerland faster than www.bahn.de thought was possible. :-)

Do you recall from your first trip the approximate length of the bus trip in minutes from Porec to Trieste?

I left from Pula, not Porec.
This site:
http://www.saf.ud.it/orariPercorsi/ts-pola.pdf
Shows a bus from Porec that leaves there at 8:30, and that arrives in Trieste at 10h40...