The state railways company said that trains bound for Crimea's regional capital of Simferopol and the port of Sevastopol will run only to stations on the mainland near Crimea starting tomorrow.
The company said the move was taken to ensure "traffic safety."
In a separate statement, the Infrastructure Ministry issued a directive to bus companies to stop bus services to Crimea starting today.
Russia annexed the Black Sea peninsula in March following the ouster of Ukraine's former Moscow-friendly president after months of protests. A pro-Russia insurgency erupted in eastern Ukraine the following month. Ukraine and the West have accused Moscow of fueling the rebellion with troops and weapons, accusations Moscow has denied.