(1) Background: Anthropometric and physical performance testing is commonly done in lifestyle research and is traditionally performed in-person. To expand the scalability of lifestyle interventions among cancer survivors, in-person assessments were adapted to remote means and evaluated for feasibility, safety, validity, and reliability. (2) Methods: Cancer survivors and supportive partners were approached to participate in three anthropometric and physical performance testing sessions (two remote/one in-person). Correlations, concordance, and differences between testing modes were evaluated. (3) Results: 110-of-112 individuals approached for testing participated (98% uptake); the sample was 78% female, 64% non-Hispanic White, of mean age 58 years and body mass index = 32.4 kg/m2. ICCs for remote assessments ranged from moderate (8’ walk = 0.47), to strong (8’ get-up-and-go = 0.74), to very strong (30 s chair stand = 0.80; sit-and-reach = 0.86; 2 min step test = 0.87; back scratch = 0.90; weight = 0.93; waist circumference = 0.98) (p-values < 0.001). Perfect concordance (100%) was found for side-by-side and semi-tandem balance, and 87.5–90.3% for tandem balance. No significant differences between remote and in-person assessments were found for weight, 8’ walk, and 8’ get-up-and-go. No adverse events occurred and 75% indicated no preference or preferred virtual testing to in-person. (4) Conclusions: Remote anthropometric and physical performance assessments are reliable, valid, acceptable, and safe among cancer survivors and supportive partners.