diff --git a/src/ImmersedBoundaries/ImmersedBoundaries.jl b/src/ImmersedBoundaries/ImmersedBoundaries.jl
index f13bdabb4b..137a8a30ab 100644
--- a/src/ImmersedBoundaries/ImmersedBoundaries.jl
+++ b/src/ImmersedBoundaries/ImmersedBoundaries.jl
@@ -91,6 +91,8 @@ import Oceananigans.TurbulenceClosures:
     νᶠᶜᶠ,
     z_bottom
 
+import Oceananigans.Fields: fractional_x_index, fractional_y_index, fractional_z_index
+
 """
     abstract type AbstractImmersedBoundary
 
@@ -235,7 +237,6 @@ As well as
 @inline immersed_inactive_node(i, j, k, ibg::IBG, LX, LY, LZ) =  inactive_node(i, j, k, ibg, LX, LY, LZ) &
                                                                 !inactive_node(i, j, k, ibg.underlying_grid, LX, LY, LZ)
 
-
 #####
 ##### Utilities
 #####
@@ -279,6 +280,10 @@ end
 
 isrectilinear(ibg::IBG) = isrectilinear(ibg.underlying_grid)
 
+@inline fractional_x_index(x, locs, grid::ImmersedBoundaryGrid) = fractional_x_index(x, locs, grid.underlying_grid) 
+@inline fractional_y_index(x, locs, grid::ImmersedBoundaryGrid) = fractional_y_index(x, locs, grid.underlying_grid) 
+@inline fractional_z_index(x, locs, grid::ImmersedBoundaryGrid) = fractional_z_index(x, locs, grid.underlying_grid) 
+
 #####
 ##### Diffusivities (for VerticallyImplicit)
 ##### (the diffusivities on the immersed boundaries are kept)