Trade union activities in the plantation sector which led to unrest in the hill country from time to time, created the need for the raising of a military unit dictated to handling internal security requirements that resulted from such trade union activity.
The 3rd (Volunteer) Battalion of the Sri Lanka Sinha Regiment was formed on 1st October 1969 with its headquarter in Nuwara Eliya and tasked to handle internal security requirements in the hill country/planting sector as and when called for.
While Major CN Panabokke of the 2nd Battalion was appointed to command the 3rd Battalion, Captain HS Hapuarachchi and Captain (QM) TFB Morseth from the 1st Ceylon Sinha Regiment were appointed as the Adjutant and the Quarter Master of the Battalion respectively. 5 officers namely Major AA de Alwis, Captain MG Ratwatte, Captain KTN de Silva, Lieutenant M Jayakumar and 2nd Lieutenant N Nilaweera along with 50 other rankers drawn from the 2nd Battalion of the Sinha Regiment made up the initial strength of the Battalion. The 1st batch of 155 recruits was trained at Diyatalawa prior to being posted to the Battalion.
In 1969, workers at the Port of Colombo struck work and troops of the 3rd Battalion were called upon to work at the Port.
In 1970, Major AA de Alwis took over the command of the Battalion.
In the early part of 1971, the Battalion was mobilized on its first tour of Task Force, Anti-Illicit Immigration (TaFII) duties at Silavathurai and was engaged in dealing with illicit immigrations and anti-smuggling duties. While the Battalion was serving in Silavathurai, the JVP insurgency broke out in April 1971. Troops were deployed in Nuwara Eliya district and most parts of the country on counter insurgency duties for the next few years.
2nd Lieutenant A Weerakoon, 2nd Lieutenant PG Perera, 2nd Lieutenant KW Jayatunge, 2nd Lieutenant K Kumaratne, 2nd Lieutenant SM Ariyaratne and 2nd Lieutenant CB Aluvihare having had completed training at Diyatalawa were posted to the Battalion in 1971.
With the country becoming a republic the name of the Battalion was also changed on 22nd May 1972 to read as the 3rd Battalion of the Sri Lanka Sinha Regiment.
Lieutenant Colonel MG Ratwatte took over command in 1975.
During the Non-Aligned Nations Conference held in 1976 in Colombo Lieutenant Colonel MG Ratwatte of the Battalion served as an extra ADC (aide-de-camp) to the President of Sri Lanka while three other officers namely Major KTN de Silva, Captain M Jayakumar and Captain N Nilaweera served as Military Liaison Officers to foreign delegations.
With communal clashes erupting in 1977 detachments of the Battalion were established in Talawakelle, Hatton, Bogawantalawa, Laxapana while all hydro power generating stations in up country were provided with security.
With the retirement of Lieutenant Colonel MG Ratwatte, Major KTN De Silva took over Command in 1978.
With the establishment of a television transmitting tower at the summit of Pidurutalagala, the Battalion was tasked to provide security for same.
Lieutenant Colonel PCR de Silva from the 1st Battalion of the Sri Lanka Sinha Regiment took over the command on 15th November 1981.
In 1984, separatist terrorists attacked the television transmitting centre at Pidurutalagala. The troops successfully repulsed the attack. Sergeant Gunatilleke JS was killed in this attack while four other soldiers were injured.
Thereafter, Lieutenant Colonel S de S Wijesekera from the Gemunu Watch, Major OB Kulasinghe from the Sinha Regiment and Lieutenant Colonel WMP Bandara from the Gemunu Watch commanded the Battalion in short spells.
