The question of whether or not SEALs join Delta Force is often debated, but the truth is that these two elite special operations units have distinct missions and requirements. The SEALs specialize in maritime operations, such as reconnaissance and counter-terrorism, and are trained to operate in various environments. On the other hand, Delta Force is an elite counter-terrorism unit that specializes in direct action and hostage rescue missions in hostile environments.
To become a SEAL, candidates must go through a rigorous selection process that includes physical and mental tests, including a six-month training program called BUD/S. Similarly, to become a Delta Force operator, candidates must first serve in the US Army and pass the SFAS and SFQC courses, followed by the secretive Delta Selection and Assessment course.
While it is not impossible for a special operator to transfer between units, it would be unlikely for a SEAL to join Delta Force due to the significant differences in training and requirements. Each unit has its own unique culture and way of operating, and it would be challenging for a SEAL to adapt to the environment and procedures of Delta Force.
Given the differences in training and missions between the two units, it is highly unlikely that a SEAL would go on to join Delta Force. While there have been cases of special operators transferring between different units, the requirements and training for each unit are so different that it would be difficult for a SEAL to meet the qualifications necessary to become a Delta Force operator. In addition, each unit has its own unique culture and way of doing things, and it would be challenging for a SEAL to adapt to the different environments and operating procedures of Delta Force.
In summary, while both the US Navy SEALs and the US Army Delta Force are highly skilled and elite special operations units, it is unlikely that a SEAL would join Delta Force due to the differences in training, qualifications, and culture between the two units.