Rinse the pork tenderloins and pat them dry with paper towels.
Combine all jerk dry-rub ingredients in a small bowl.
Season the pork with the jerk dry rub on all sides.
Heat a non-stick skillet or cast-iron skillet over high heat until really hot, add olive oil, and immediately sear the seasoned pork, 30 seconds on each side. Remove from heat.
Allow the seared pork to cool down a bit, then place it in a large Ziploc bag or a vacuum sealer bag, add the rosemary if using.
Use the water displacement method to submerge the bag in the sous vide water bath and set the timer for 1.5 hours. (Please note that you can still use the water displacement method with a vacuum sealer bag. But if you prefer, feel free to vacuum seal the bag.)
Once the timer goes off. Remove the pork from the water bath. Open the bag and transfer the pork to a cutting board. Slice and enjoy.