At the end of April, it is still cool on the Black Sea in Anapa, the air temperature ranges on average from +12°C to +20 °C. The water temperature in the sea is still quite low, about +10°C- +12 °C, so it will be quite cold to swim.
At Anapa resort at this time of year, you can visit museums and attractions such as the Russian Gate, the museum and the Gorgippia excavation site. You can also walk along the embankment and visit local cafes and restaurants. If you like active recreation, then you can go cycling around the neighborhood or play bowling. In any case, Anapa is not crowded with tourists at this time of year, so you can enjoy a relaxing holiday, take a walk along the Black Sea coast, go fishing from the pier or from a boat, go for a boat trip on a sailing yacht.
God bless you. Have a nice day!