Older adult education is still under-researched, with many terminological ambiguities, clichés, and prejudices. Older adult teacher education and older adult English as a foreign language (EFL) teacher education is rare. Many factors can influence EFL teachers of older adults' teaching performance and its perception. Pre-service (presumably inexperienced U3A EFL teachers) and in-service teachers (experienced U3A EFL) were teaching EFL to selected older adults (aged from 64 to 75 years) at the Karkonosze University of Applied Sciences in Jelenia Góra, Poland, U3A. Their teaching Older adult education is still under-researched, with many terminological ambiguities, clichés, and prejudices. Older adult teacher education and older adult English as a foreign language (EFL) teacher education is rare. Many facting performance factors list. By utilizing a critical foreign language geragogy and a strengths-based approach inspired by positive psychology, the research emphasized the role of general teaching experience and/or age-targeted teaching experience. And it led to validating the desirable teaching performance factors as factors that defined U3A EFL teaching performance as successful and positively evaluated by given older adult learners, i.e. on a small scale.