Mix whole wheat flour, yeast, salt, and sugar in a bowl.
Gradually add lukewarm water and knead the dough.
Knead the dough thoroughly for 10 minutes until it is soft and elastic.
Shape the dough into rounds and poke a hole in the center to form bagels.
Cover with a damp cloth and let rise for about 1 hour.
Boil the bagels in hot water for 30 seconds on each side.
Bake in a preheated oven at 180°C for 20 minutes.