IWI can be qualified or certified at three different levels:

• IWI at the basic Level (IWI-B) have the skills to perform Visual Inspection of Welds and may perform other inspection tasks to assist other welding inspectors.
• IWI at the Standard Level (IWI-S) have the skill to perform any inspection task as required by a standard or a code.
• IWI at the Comprehensive level (IWI-C) have skills and knowledge to allow performing any welding inspection task, even in non-conventional applications concerning materials, processes, advanced destructive testing and NDT and even where no specific code is available, as they may develop welding inspection or quality control plans.

Different routes are applicable to gain an IIW diploma. They include direct access to training at each level, based on specific access conditions, and a career progression opportunity that allows undergoing a qualification path through different levels supported by experience.

Certification requires also appropriate experience at the specific level. All candidates undergo an examination that includes theory, practices and hands-on exercises that simulate the various inspection tasks (Visual Inspection, verification of documents, and assessment of production documents against standards).