A review of surface circulation in the Norwegian, Greenland, and Barents seas is presented. Measurements of oceanographic characteristics, currents, and tides in the Fram Strait and Greenland Sea are analyzed using measurement on moorings. It is shown that the speeds of the East Greenland and West Spitsbergen currents are low while the velocities of tidal currents in the region are two or more times greater. Tidal currents are intensifying on the shelf of Greenland and Spitsbergen. Direct measurements agree with Oregon State University barotropic tide model. We also studied overflow of bottom waters through the Strait of Denmark to the Atlantic. A unique hydrodynamic effect has been found. A large volume of cold mixed water overflows as a lens, which is called bolus. It was shown that the transversal size of the bolus limited by the 1.028 g/cm3 isopycnal is 35–40 miles. Its thickness reaches 300 m. This form of overflow over the sill in the form of bolus alternates with a period of 5 days with the usual overflow. During the bolus overflow, the maximum velocities are found at the leading front, when the water descends down the sill. Minimum velocities are found in the middle of the bolus, which is caused by widening of the bolus after it passes the narrow part of the strait and widens. Velocities increase again in the rear part of the bolus in the narrows of the strait. We suggest a mechanism of 5-day variation of the overflow regime, which is governed by internal seiches.