In order to control the grave interference in mobile ambient (MA), Levi et al. proposed mobile safe ambients (SA). However, the coactions introduced in SA brought new security breaches. In this paper, robust ambients (ROAM) is proposed to eliminate those security breaches. In ROAM, coactions are still utilized to control the grave interference. In addition, the parameter of every coaction is explicitly specified to name the consumer of that coaction. This mechanism effectively eliminates the security breaches in SA.THe firewall crossing example and the encoding of polyadic asynchonous π-calculus in ROAM show that ROAM still keeps the strong expressiveness of its ancestors.A fundamental tupe system for ROAM with both thread count and mobility attibutes is also proposed and proved.The result in this paper shows that ROAM is a good candidate in the formalization of mobile computation.