diff --git a/src/bases_dirac.jl b/src/bases_dirac.jl
index 75d7918..48a917f 100644
--- a/src/bases_dirac.jl
+++ b/src/bases_dirac.jl
@@ -101,6 +101,8 @@ function MappedBasis(itr, map, inverse_map)
     return MappedBasis{typeof(map(first(itr)))}(itr, map, inverse_map)
 end
 
+Base.copy(b::MappedBasis) = b
+
 object(db::MappedBasis) = db.object
 
 function Base.IteratorSize(::Type{<:MappedBasis{T,I,S}}) where {T,I,S}
diff --git a/src/bases_fixed.jl b/src/bases_fixed.jl
index 5273279..1ac67ff 100644
--- a/src/bases_fixed.jl
+++ b/src/bases_fixed.jl
@@ -106,6 +106,8 @@ struct SubBasis{T,I,K,B<:AbstractBasis{T,K},V<:AbstractVector{K}} <:
     end
 end
 
+Base.copy(b::SubBasis) = SubBasis(copy(parent(b)), copy(b.keys))
+
 Base.parent(sub::SubBasis) = sub.parent_basis
 
 Base.length(b::SubBasis) = length(b.keys)