From the parking lot with the signpost to the northernmost point, it's about 500 m through the dunes to the beach, and then another 300 m to the right to the actual point with the sign. By bike, it's only about 250 m, which requires a lot of skill, so it's better to leave it at home and walk, which is permitted and encouraged.
Interesting fact: On the occasion of German Unity Day in 1999, the municipalities of Germany's northernmost, southernmost, western, and easternmost regions joined forces to form the "Zipfelbund" (Zipfel Association). In the north, this northernmost point of Germany is located here in the municipality of List on Sylt. Other Zipfel regions are in the Selfkant region (western region in the Heinsberg district), the city of Görlitz (east), and Oberstdorf (southern Germany). There's a challenge at zipfelbund.de where you can get stamps for visiting all the Zipfel locations.