No. It's not possible to SCUBA dive to the titanic. The titanic currently lies over 12,000 feet (3,700 m) below the surface of the ocean. At this depth, the water pressure is over 6,500 pounds per square inch.
Currently the Guinness world record for a dive on SCUBA gear was set by Ahmed Gabr, 41 on September 22, 2014 by diving to a record 1090 feet and 4.5 inches (link here). This broke the previous world record of 1,044 feet set in 2005 by Nuno Gomes.