I bet you could do it with a big enough expense account with Planet Labs and the compute power to process the images these days. Track it forwards from the last public port of call or *INT leak like this strava data. 3.7m accuracy seems like enough to do it. It's not enough to target it directly but it would be enough to get more capable assets into the right area a la the interception of Japan's ships when they attacked Midway.
Iran, like most countries, does not a blue water navy with assets in the Mediterranean sea to perform realtime surveillance.
They had a handful of frigates mostly but those could go out as far as the Med pretty easily. One of their ships was sunk near Sri Lanka.
It was sunk there because it attended an on-off event in India before that. Iran's ships don't get on regular trips far from home.