The research titled “THE IMPLEMENTATION OF FLEXIBLE LEARNING IN ENGLISH: INPUT FOR PRACTICE SUSTAINABILITY” this study aimed to find out the status of implementation of Modular and Online Distance Learning, the performance of first quarter grade in English, problems met by students and teachers, the level of involvement of parents and the level of readiness of school. Thirty eight (38) thirty eight (38) English Teachers from Pedro Guevara Memorial National High School, ten (10) English Teachers from Gov,Felicisimo T. San Luis Integrated Senior High School and selected fifty (50) students from Santa Cruz District were requested to participate in the study. The research design used in this study was descriptive method of research. Random Sampling was used and the statistical treatment of data such as mean, standard deviation, f-value and p-value was used to compute, analyze the given data and interpret it. Analysis revealed that the status of implementation of flexible learning modalities: Input for practice sustainability can contribute to further improve the modality by knowing the different problems encountered by teachers and students as well as their perception. Parent’s involvement in the utilization of flexible learning influenced learners to be motivated and enjoy answering the learning task. Schools have materials to produce modules and do some alternatives to make study possible. The effect of flexible learning modalities to the first quarter performance in English confirms that Modular distance learning (print), modular distance learning (digital), online distance learning (synchronous) does not have the significant effect on the flexible learning modalities on the first quarter performance of the students in English while online distance learning (asynchronous) have a significant effect on the flexible learning modalities on the first quarter performance of the students in English. Majority of the modalities does not have a significant effect on the first quarter grade of the learners. When it comes to the effect of flexible learning modalities to the readiness of school, It shows that modular distance learning (print) and modular distance learning (digital) have significant effect on the flexible learning modalities to the level of school readiness then online distance learning (synchronous) and online distance learning (asynchronous) does not have a significant effect on the flexible learning modalities to the level of school readiness. It only means that the hypothesis is partially accepted.