Seyðisfjörður is a city in East Iceland.
There is a weekly ferry run by Smyril line to Denmark and the Faroe Islands. The schedule is horrendously complicated but it generally departs once per week at 8AM during the summer half the year (April-June and August-October) , and at 1PM during high season (June-August). Check website for details. Due to the limited market, and rough conditions, prices are very high. A return journey to Denmark for instance will set you back 280-590 EUR depending on the season, excluding supplement for a cabin or bed.