Sealyham is not as fierce as compared to the other terrier breeds but instead it is calmer by nature. However, bear in mind that even with its laid-back attitude, it still needs constant exercise and activities. This breed loves to hunt and would protect its territory.
It is known to be an independent dog but loyal to its family. Inheriting from the terriers, it has a pretty high prey drive. It is smart, a fast learner, independent, and often stubborn that requires training lessons. For that reason, it is not the best choice for first-time owners.
Just like any other dogs, the Sealyham Terrier needs socialisation so it will grow up to be an outgoing mature dog. Gradual exposure to noises, people and other animals are recommended after they have been fully vaccinated. Keep your eye on your dog during public walks because it is naturally curious and could wander alone.