B1/B2 need to travel

[abce1234]

Hi,

My parents got the visitors B1/B2 VISA.

Is there any mandatory rule, that they need to travel to USA once, in next 180 days from the date of VISA issued?

Response/help is appreciated.

Thanks

[ramabalaji]

There is no such rule. They can travel to USA even on the last day of the expiry of their visitor visa.