Azalea plant named 'RLH1-10P18'

A new and distinct cultivar of Azalea plant named 'RLH1-10P18', characterized by its upright to outwardly spreading and mounding plant habit; freely basal branching habit; dense and bushy appearance; vigorous growth habit and rapid growth rate; evergreen, persistent dark green-colored leaves that do not abscise during the winter; freely flowering habit with remontant flowering during the spring, summer and autumn; large, non-persistent semi-double to double flowers that are dark red in color with darker red-colored central spots and speckles; and excellent garden performance and temperature tolerance.