Climate change is triggering environmental mobility through chronic water problems and punctuated events. Thinking about moving locations, or “mobility ideation”, is the precursor to migration intentionality and actual migration. Drawing on the embodiment construct, this study examines how the worst drought in recent history in the Horn of Africa affected water-related mobility ideation and, in turn, fingernail cortisol concentration (FCC), a chronic stress biomarker, among Daasanach semi-nomadic pastoralists in northern Kenya. To address these questions, we primarily draw on survey, anthropometric, water quality, and biomarker data among 175 adults living in seven communities in 2022. We used mixed-effects ordered logistic regression to test how livestock wealth, water insecurity, food insecurity, and anxiety/depression symptom scores were associated with household mobility ideation. We then used generalized linear models to test the association between mobility ideation on FCC. Thinking about moving at least once due to water problems increased from pre-drought in 2019 (55%) to during the drought in 2022 (92%), while actual mobility declined. Livestock wealth, while associated with actual mobility in the prior year, was protective against increased mobility ideation, while water insecurity, food insecurity, and anxiety/depression symptoms were associated with greater odds of thinking of leaving in 2022. Compared to adults who did not consider moving, those who considered moving rarely, sometimes, and often had FCC levels 18.1% higher (95% CI, 1.01–1.38; p = 0.039), 19.4% higher (1.01–1.41; p = 0.040), and 32.3% higher (1.01–1.73; p = 0.039), respectively, with results consistent in sensitivity analyses. Extreme climatic events in water scarce regions may increase mobility ideation through worsened experiential indicators of well-being and resource insecurity. Mobility ideation may capture measures of adversity suffered by pastoralists and signify climate distress. This research broadens understanding of how droughts get under the skin by leading to resource insecurity and triggering thoughts of moving, which increases chronic stress.