This study investigated the effect of preschool-wide, teacher-implemented, phoneme-focused phonological awareness (PA) and letter-sound knowledge (LSK) instruction, on raising code-based school-entry reading readiness for children with Spoken Language Difficulties (SLD) and Typical Development (TD), when supported by weekly coaching by trainee speech-language pathologists. A total of 90 4-year-old children participated, whereby 50 children, inclusive of 13 children with SLD, received 10 weeks of preschool-wide, teacher-delivered, phoneme-focused PA and LSK instruction. In all, 40 children, inclusive of 10 children with SLD, continued with the usual preschool program. Post-instruction, children in the experimental condition performed significantly higher in phoneme awareness, LSK, and early decoding compared with control children. Children with SLD in the experimental condition performed significantly higher in phoneme awareness and LSK, but not in early decoding, compared with control children with SLD. Overall, preschool-wide, teacher-implemented, phoneme-focused PA and LSK instruction can support code-based reading readiness skills for children with SLD and TD.