B767 First Officer reported high vibration on the right engine. The flight crew performed an air turn back and precautionary landing at departure airport.

Narrative

At around XA20 I exited the cockpit to start my rest. Around 20 minutes later the Lead Flight Attendant notified me that I was needed in the cockpit as there was something going on with the engine. I reentered the cockpit and was brought up to speed by the Captain and First Officer. They explained to me that the right engine had been exhibiting high vibrations all throughout the climb. When I entered the cockpit the vibrations were oscillating between 3.7-4.2. The Captain had laid out a plan to use all available crew to pinpoint the problem. He had me take over radios while he flew the airplane and the First Officer went back into the cabin to listen for any abnormal sounds or vibrations. While doing this the Captain was on the SAT phone with Maintenance while they went over some troubleshooting steps. The First Officer reentered the cockpit and assumed his seat while I went back into my relief pilot seat. We all talked about the threat being the high engine vibration on the right engine and did not feel it was the safest course of action to take the airplane over the ocean with a potentially damaged engine. We all agreed the best course of action would be to return to ZZZ. During this entire time engine vibrations remained above 3.5. After coordinating our intentions with ATC and Dispatch we were given a heading and later a full arrival clearance into ZZZ. We prepared all checklist for a possible engine surge and possible engine shut down and talked about the plan in case the engine did completely fail. After everyone in the crew had a shared mental model; the arrival and the approach was briefed; and the Captain flew a normal approach back into ZZZ for the ILS XR; to a normal touchdown and rollout. We taxied to the gate under our own power and ran a parking checklist. Maintenance met the airplane and the Captain briefed the maintenance personnel on the situation.