From April 25, 2018, the Tourist Card is included in all air tickets issued outside the Dominican Republic, however all passengers entering by air to the DOM, with air tickets purchased before that date, must submit the corresponding Tourist Card.  

We emphasize that we will continue to receive all Tourist Cards previously purchased by passengers whose tickets do not include it.

For visitors entering the country by land or sea, Tourist Cards can be purchased at the points of sale of the Directorate General of Internal Taxes at a value of $10.00 US or
€ 10.00. 

For more information visit: http://www.dgii.gov.do/tarjetaTuristica/sobreTarjetaT/Paginas/default.aspx