Open all year during reasonable daylight hours; no admission charge. Cadw may close monuments at short notice in extreme weather.
Terrain level 2, easy: a grass field path and a railed footbridge over deep water onto the platform; surfaces may be slippery or uneven and the moat edges are unfenced. No facilities. Drones are not permitted.
Dogs: Cadw: 'Dogs welcome. Dogs on short leads welcome to access ground floor levels of the site.' An open-air site on Cadw's dog-friendly list for south-east Wales, which asks for dogs under control and on a short lead at all times; deep water in the moat.
Photo: The water-filled moat at Hen Gwrt, Llantilio Crossenny, with the timber footbridge onto the grassy moated platform among spring trees. KJP1, CC BY-SA 4.0. Source: https://commons.wikimedia.org/wiki/File:Hen_Gwrt,_Llantilio_Crossenny,_Monmouthshire,_UK.jpg. Licence: https://creativecommons.org/licenses/by-sa/4.0. Resized and cropped for display; derivatives retain the source licence.