Obviously you can only dig for lugworm when the tide is out. That means from two hours before until two hours after low tide in most areas. (The window for black lug is a lot smaller.) In the winter, when the worms are deep, it can be easier to dig when the tide is coming in because the worms come up a bit.
Where can I get Lugworms?
Lugworms can be purchased from the fishing shop at Seafront. They can be purchased for 10 gold and sold for 2 gold.
Where can I dig lugworm Northeast?
Bran Sands beach is well known as one of the North-east's best spots for collecting ragworms and lugworms. At low tide fishermen descend on the beach to dig up the worms they need for bait to catch cod.