It's been a while since we've heard a rumor about a smartwatch coming from OnePlus, but it's once again time. This time, it might actually be happening though. A certification on Singapore's IMDA (via 91mobiles) shows something called the OnePlus Watch with the model name W301GB and a description of 'Wearable Watch'.
Aside from showing up in public filings, another reason that now might be the time for OnePlus to launch a smartwatch is because Oppo did it with the Oppo Watch. Both Oppo and OnePlus are owned by BBK Electronics. That's why you'll often see similar designs from the two firms, along with Vivo and Realme, and why when a feature shows up on one brand, it often shows up on another.
Nothing else is known at this point about the OnePlus Watch at this time, so while it seems likely that it's coming, don't expect to see it overnight. It's likely that we'll start seeing some actual leaks before it launches. Perhaps, the Shenzhen firm will launch its smartwatch this fall alongside the OnePlus 8T series.