The company, which has cancelled all trips to Russia until the end of June, has since decided to stop all sales to the country.
It has also donated to the Red Cross and collated a selection of ways its team members have been helping to support the cause, including donating essential items to a local church in Farnborough needed for refugees crossing into Poland.
Explore staff are also working within their own communities to gather items in partnership with schools and community centres.
In a statement, the company said it has been "hugely concerned" for the people of Ukraine since news broke of the invasion and are "intent on helping in any way we can".
"We are in daily contact with our suppliers and partners, both in Russia and Ukraine, and supporting them wherever we can," it added.
"We’re huge believers in the power of small group travel as a way to ensure that tourism brings benefit – both financially and culturally – to the places we visit.
"And, where we can do it safely and in a way that supports the communities we visit, we usually do it regardless of the regime in charge. On this occasion, though, we have decided to stop all sales of trips to Russia."
Explore said it "emphatically condemns" Russia’s invasion of Ukraine, and stands with the Ukrainian people in the defence of their nation.