21 January – A 44 year old motorist was shot dead in Kataragama by the police after defying the orders when riding the motorcycle, which led to turmoil and confusion in the Kataragama area as the police opened tear gas to control and disperse bystanders after the unusual incident at the religious area.[1]
23 January – The official trophy for the 2018 FIFA World Cup was brought to Sri Lanka and was kept in Colombo for 2 days and was displayed to the public as part of the 2018 FIFA World Cup Trophy Tour, in which the trophy would travel across 52 nations. This was the first time Sri Lanka was selected as one of the nations to officially showcase the trophy in history.[2][3]
23 February – Komaali Kings, a Sri Lankan Tamil-language film released on this day becomes the first Sri Lankan Tamil-language mass-budgeted film in 40 years. The film also marks the rebirth of Sri Lankan Tamil Cinema as it released in across 50 theatres in the nation.[8]
27 February – 2018 anti-Muslim riots in Sri Lanka: Riots began in the town of Ampara between Sinhalese and Muslim groups. Mosques, restaurants and muslim civilians were targeted during the riots over alleged rumours that unwanted chemicals were being added to food items in Muslim restaurants, within the vicinity of the temple junction in Ampara.[9]
2 March – 2018 anti-Muslim riots in Sri Lanka: Riots began spreading from Udispattuwa and Teldeniya to Digana and other areas in the Kandy District. Several Muslim businesses, mosques and shops were attacked by Sinhalese mobs following the death of a Buddhist male following an assault by 4 intoxicated Muslim youths on 22 February. Following the violence in Kandy, the Sri Lankan government declared a state of emergency across the nation for 10 days.[10]
6 March – 2018 Nidahas Trophy was a Tri-Nations tournament held from 6 March to 18 March to celebrate 70 years of Sri Lankan independence.
2 May – The final rites of the veteran film director Lester James Peiris proceeded with the state patronage.[12]
19 May – Floods began as a result of heavy rainfall, starting from 19 May, resulting in severe damages throughout the island. The floods left 13 dead, 23 missing and over 100,000 affected due to torrential floods.[13][14]
24 May – Ranjan de Silva, politician and father of Sri Lankan national cricketer Dhananjaya de Silva, was shot dead by unknown people.[15][16]
Sri Lankan marine biologist Asha de Vos was awarded the Golden Alumni Award in the Professional Achievement category at the first edition of the British Council Golden Alumni awards.[19]
28 May – Sri Lankan veteran film and teledrama actress Deepani Silva was arrested and released on bail by the Bandaragama Police for her involvement in a car accident with three wheeler which left a 10-year-old child critically injured.[20][21][22][23]
31 May
The Sri Lankan Cricket Elections which were scheduled to be held on 31 May 2018 were cancelled the day before following a stay order issued by the Court of Appeal, after a petition was filed against Sri Lankan Cricket Board president Thilanga Sumathipala contesting in the elections.[24][25]
A new map of Sri Lanka was officially released, with updates on Colombo City jointly with the Colombo Port city.[26] This was the first time the map of Sri Lanka was renewed in 18 years.[27]
It was reported that Sri Lanka is going to reinstate Capital punishment for drug dealers, president Maithripala Sirisena told the government, which earlier had unanimously backed the reinstatement of capital punishment, that he "was ready to sign the death warrants".[31]
The ICC concluded its hearing on the trio including Dinesh Chandimal, who had pleaded guilty to a level three spirit of cricket offence. His hearing took place before the start of the first Test against South Africa, with him found guilty. He received a two-match ban, with Suranga Lakmal captaining the side in his place.[32][33]
15 July – The scheduled inaugural edition of the Lankan Premier League which was supposed to be held in August 2018 was indefinitely postponed as a result of the change in country's cricket administration.[34][35]
16 July – The independent Judicial Commissioner handed down a further eight suspension points with maximum possible punishment for their spirit of cricket offence and suspended Chandimal for four ODIs as well.[36][37]
18 August – Akalanka Peiris became the first ever Sri Lankan student to sit for a Sri Lankan GCE A/L examinations outside Sri Lanka as he was granted special permission to write A/L exams in Jakarta, Indonesia just prior to his preparations for the 2018 Asian Games.[38][39]
26 August – Sri Lanka clinched maiden Carrom World Cup title in men's team event defeating defending champion India at the 2018 Carrom World Cup and also secured the second place in the women's team event.[40][41][42]
29 September – The BMS Campus (Business Management School) of Sri Lanka won the 2018 edition of the Red Bull Campus Cricket World Finals by 4 wickets to lift its second world title.[53]
2018 Sri Lankan constitutional crisis: The Constitutional Court rules President Sirisena's dissolution of parliament illegal. Mahinda Rajapaksa fails to form a government that commands a parliamentary majority and Prime Minister Ranil Wickremesinghe reassumes office.
2018 Sri Lankan constitutional crisis: President Maithripala Sirisena reinstates Ranil Wickremesinghe in the position of Prime Minister, ending the constitutional coup.
Lucion Pushparaj became the first ever Sri Lankan to win the World Bodybuilding Championship during the 2018 World Bodybuilding Championship.[63]