Can implantation occur 3 dpo? (days past ovulation)

Yes: Once the egg is fertilized it takes about 2 to 3 days to travel through the fallopian tube to implant in the lining of the uterus(endometrium).

Nope! Too early: Whatever day your ovulation occurs, fertilization (if it happens) will be within roughly 24 hours (1 day.) an embryo will travel into the uterus within about 3 days p.O. But will not implant until between the 6th and 7th day p.O.