Yes, the country is open. However, you will need the following to travel to Sri Lanka:

1. Covid-19 insurance coverage, purchased here
2. ETA Visa Approval via email
3. Completed Health Declaration Form

Find more information here.

Yes, a travel visa is required for arrival. You can start the quick process here. 

There is no quarantine required if you are fully vaccinated (having completed the recommended number of doses 14 days prior to arriving in Sri Lanka). Even if you’re not fully vaccinated, you can still travel to Sri Lanka and not be quarantined, but you will be restricted to a tourist bio-bubble for certain approved hotels and excursions only. You can read more here.