Frogs of Borneo assures me that this is a common lowland stream toad, though I saw only one in two nights full of frogs at Kubah National Park. A fully grown specimen is about an inch long.

My Travelogues and Trip Lists page includes a complete list of the herps I saw in the wild on this trip to Malaysia, as well as a travelogue of the trip.

I saw one more in the same area at Kubah the next year, so maybe that's enough to call them common?