Soba is noodles made from buckwheat flour added with water and kneaded into a dough.Then it is rolled out and finely cut. Soba is enjoyed hot in a broth or cold with dipping in a sauce. Both these dishes are served with side dishes (such as tempura and grated Chinese yam) or garnish (such as green onion & nori seaweed).
  Tsukimi Soba
japanesefood/soba
  Cold Soba
japanesefood/soba
 
Tempura Soba Set
japanesefood/soba
Udon is made from flour and salt. It is kneaded into a dough and cut into hearty noodles. The characteristics are its white color and smooth texture. Udon varieties are served with side dishes (such as tempura, deep fried Tofu, or egg) and garnish (such as green onion).
  Kitsune Udon
japanesefood/udon
Zaru Udon
japanesefood/udon
 
Zaru-Udon
Udon is enjoyed cold with a dipping sauce or a sauce that is poured over the noodles. Zaru udon is served with side dishes (such as tempura) and garnish (such as grated ginger and Japanese radish, green onion, and shredded nori seaweed).

All image photos and descriotion above are just samples.
Dishes are served in many ways depend on locations where you visit
.