Standard financial assets have not proven to be effective tools to meet the objective of raising sufficient private capital for biodiversity protection. How to finance a reversal in biodiversity deterioration remains a challenge. In this chapter, we propose a model of Biodiversity-related Sustainability-Linked Bonds (BrSLBs) as an innovative financing instrument for biodiversity conservation and restoration. Following an option pricing approach, we derive a pricing model where the Key Performance Indicator (KPI) is related to the issue of contrasting biodiversity loss and nature deterioration. We propose a comprehensive pricing formula for BrSLBs that is based on multivariate digital options and accounts both for the KPI provision and the issuers’ credit risk. We then investigate a series of relevant questions regarding these instruments, for example, the existence of a “bio-sustainium,” the interaction between sustainability performance and issuer’s credit risk, the optimal design of these bonds, and potential greenwashing. The chapter contributes to the understanding and expansion of sustainable finance and offers solutions for funding biodiversity preservation.