diff --git a/src/script/solver.h b/src/script/solver.h
index 5a7b685a6f5..5b945477c90 100644
--- a/src/script/solver.h
+++ b/src/script/solver.h
@@ -10,6 +10,7 @@
 
 #include <attributes.h>
 #include <script/script.h>
+#include <span.h>
 
 #include <string>
 #include <optional>
@@ -17,7 +18,6 @@
 #include <vector>
 
 class CPubKey;
-template <typename C> class Span;
 
 enum class TxoutType {
     NONSTANDARD,
diff --git a/src/test/util/net.h b/src/test/util/net.h
index 043e317bf08..d3aefda4f0e 100644
--- a/src/test/util/net.h
+++ b/src/test/util/net.h
@@ -12,6 +12,7 @@
 #include <netaddress.h>
 #include <node/connection_types.h>
 #include <node/eviction.h>
+#include <span.h>
 #include <sync.h>
 #include <util/sock.h>
 
@@ -28,9 +29,6 @@
 
 class FastRandomContext;
 
-template <typename C>
-class Span;
-
 struct ConnmanTestMsg : public CConnman {
     using CConnman::CConnman;
 
diff --git a/src/util/hasher.h b/src/util/hasher.h
index 3ad6d5bb94c..e4594c7ddaf 100644
--- a/src/util/hasher.h
+++ b/src/util/hasher.h
@@ -8,13 +8,12 @@
 #include <crypto/common.h>
 #include <crypto/siphash.h>
 #include <primitives/transaction.h>
+#include <span.h>
 #include <uint256.h>
 
 #include <cstdint>
 #include <cstring>
 
-template <typename C> class Span;
-
 class SaltedTxidHasher
 {
 private: