Their aircraft was seized earlier this month carrying military equipment bound for the neighbouring semi-autonomous state of Puntland.
A court sentenced them to a year in jail and fined them for supplying military equipment to an enemy.
The charterer of the plane, Saracens International, denied that the cargo was illegal.
The Russians were also convicted of violating Somaliland's airspace and fined $500 (£320). The uniforms and mines which were found on board the aircraft were confiscated by the court in the Somaliland capital, Hargeisa.
Reports say the Russians were told that if they paid a larger fine they would serve a shorter sentence.
Some South African journalists on the plane, which had landed without permission in Hargeisa to refuel, were released earlier.
BBC Africa analyst Martin Plaut says that this is a very murky case and that many elements of it are unclear.
Disputed territory
After the Russians were arrested the interior minister of Somaliland, Mohamed Abdi Gaboosi, said the cargo was in violation of the United Nations arms embargo on Somalia.
Saracens - a private military contractor, which is based in Uganda and South Africa - told the BBC at the time that the cargo was destined for its operation in Puntland, where it is training an anti-piracy force.
Somaliland declared itself independent from Somalia in the early 1990s, but is not internationally recognised. It is relatively stable, unlike the rest of Somalia, and even organises regular elections.
However, it has a border dispute with Puntland and the two security forces occasionally clash.
Unlike Somaliland, Puntland says it does not seek recognition as an independent entity, wishing instead to be part of a federal Somalia.
Somalia has not had an effective national government since 1991
Russians will be on their way back to moscow after jalle putin has a word with fatboy siilanyo and promises him a year of supply of russia's finest borsch.
