diff --git a/src/crashlog.cpp b/src/crashlog.cpp
index 6382d81e4b..848424d058 100644
--- a/src/crashlog.cpp
+++ b/src/crashlog.cpp
@@ -478,45 +478,45 @@ bool CrashLog::MakeCrashLog() const
 	char buffer[65536];
 	bool ret = true;
 
-	printf("Crash encountered, generating crash log...\n");
+	fmt::print("Crash encountered, generating crash log...\n");
 	this->FillCrashLog(buffer, lastof(buffer));
-	printf("%s\n", buffer);
-	printf("Crash log generated.\n\n");
+	fmt::print("{}\n", buffer);
+	fmt::print("Crash log generated.\n\n");
 
-	printf("Writing crash log to disk...\n");
+	fmt::print("Writing crash log to disk...\n");
 	bool bret = this->WriteCrashLog(buffer, filename, lastof(filename));
 	if (bret) {
-		printf("Crash log written to %s. Please add this file to any bug reports.\n\n", filename);
+		fmt::print("Crash log written to {}. Please add this file to any bug reports.\n\n", filename);
 	} else {
-		printf("Writing crash log failed. Please attach the output above to any bug reports.\n\n");
+		fmt::print("Writing crash log failed. Please attach the output above to any bug reports.\n\n");
 		ret = false;
 	}
 
 	/* Don't mention writing crash dumps because not all platforms support it. */
 	int dret = this->WriteCrashDump(filename, lastof(filename));
 	if (dret < 0) {
-		printf("Writing crash dump failed.\n\n");
+		fmt::print("Writing crash dump failed.\n\n");
 		ret = false;
 	} else if (dret > 0) {
-		printf("Crash dump written to %s. Please add this file to any bug reports.\n\n", filename);
+		fmt::print("Crash dump written to {}. Please add this file to any bug reports.\n\n", filename);
 	}
 
-	printf("Writing crash savegame...\n");
+	fmt::print("Writing crash savegame...\n");
 	bret = this->WriteSavegame(filename, lastof(filename));
 	if (bret) {
-		printf("Crash savegame written to %s. Please add this file and the last (auto)save to any bug reports.\n\n", filename);
+		fmt::print("Crash savegame written to {}. Please add this file and the last (auto)save to any bug reports.\n\n", filename);
 	} else {
 		ret = false;
-		printf("Writing crash savegame failed. Please attach the last (auto)save to any bug reports.\n\n");
+		fmt::print("Writing crash savegame failed. Please attach the last (auto)save to any bug reports.\n\n");
 	}
 
-	printf("Writing crash screenshot...\n");
+	fmt::print("Writing crash screenshot...\n");
 	bret = this->WriteScreenshot(filename, lastof(filename));
 	if (bret) {
-		printf("Crash screenshot written to %s. Please add this file to any bug reports.\n\n", filename);
+		fmt::print("Crash screenshot written to {}. Please add this file to any bug reports.\n\n", filename);
 	} else {
 		ret = false;
-		printf("Writing crash screenshot failed.\n\n");
+		fmt::print("Writing crash screenshot failed.\n\n");
 	}
 
 	this->SendSurvey();
diff --git a/src/network/network_chat_gui.cpp b/src/network/network_chat_gui.cpp
index aadee357e0..01aad5fb7a 100644
--- a/src/network/network_chat_gui.cpp
+++ b/src/network/network_chat_gui.cpp
@@ -85,7 +85,7 @@ static inline bool HaveChatMessages(bool show_all)
  * Add a text message to the 'chat window' to be shown
  * @param colour The colour this message is to be shown in
  * @param duration The duration of the chat message in seconds
- * @param message message itself in printf() style
+ * @param message message itself
  */
 void CDECL NetworkAddChatMessage(TextColour colour, uint duration, const std::string &message)
 {
diff --git a/src/openttd.cpp b/src/openttd.cpp
index 61c0e1da9d..d7f0d064e8 100644
--- a/src/openttd.cpp
+++ b/src/openttd.cpp
@@ -225,7 +225,7 @@ static void ShowHelp()
 	/* ShowInfo put output to stderr, but version information should go
 	 * to stdout; this is the only exception */
 #if !defined(_WIN32)
-	printf("%s\n", str.c_str());
+	fmt::print("{}\n", str);
 #else
 	ShowInfoI(str);
 #endif
@@ -262,7 +262,7 @@ static void WriteSavegameInfo(const char *name)
 	/* ShowInfo put output to stderr, but version information should go
 	 * to stdout; this is the only exception */
 #if !defined(_WIN32)
-	printf("%s\n", message.c_str());
+	fmt::print("%s\n", message);
 #else
 	ShowInfoI(message);
 #endif
diff --git a/src/os/macosx/crashlog_osx.cpp b/src/os/macosx/crashlog_osx.cpp
index df1736a6f6..0b1b303c2c 100644
--- a/src/os/macosx/crashlog_osx.cpp
+++ b/src/os/macosx/crashlog_osx.cpp
@@ -169,24 +169,24 @@ public:
 		char buffer[65536];
 		bool ret = true;
 
-		printf("Crash encountered, generating crash log...\n");
+		fmt::print("Crash encountered, generating crash log...\n");
 		this->FillCrashLog(buffer, lastof(buffer));
-		printf("%s\n", buffer);
-		printf("Crash log generated.\n\n");
+		fmt::print("{}\n", buffer);
+		fmt::print("Crash log generated.\n\n");
 
-		printf("Writing crash log to disk...\n");
+		fmt::print("Writing crash log to disk...\n");
 		if (!this->WriteCrashLog(buffer, filename_log, lastof(filename_log))) {
 			filename_log[0] = '\0';
 			ret = false;
 		}
 
-		printf("Writing crash savegame...\n");
+		fmt::print("Writing crash savegame...\n");
 		if (!this->WriteSavegame(filename_save, lastof(filename_save))) {
 			filename_save[0] = '\0';
 			ret = false;
 		}
 
-		printf("Writing crash screenshot...\n");
+		fmt::print("Writing crash screenshot...\n");
 		if (!this->WriteScreenshot(filename_screenshot, lastof(filename_screenshot))) {
 			filename_screenshot[0] = '\0';
 			ret = false;
diff --git a/src/os/unix/crashlog_unix.cpp b/src/os/unix/crashlog_unix.cpp
index a3fc1d5e97..dcbad13d70 100644
--- a/src/os/unix/crashlog_unix.cpp
+++ b/src/os/unix/crashlog_unix.cpp
@@ -156,15 +156,15 @@ static void CDECL HandleCrash(int signum)
 	}
 
 	if (_gamelog.TestEmergency()) {
-		printf("A serious fault condition occurred in the game. The game will shut down.\n");
-		printf("As you loaded an emergency savegame no crash information will be generated.\n");
+		fmt::print("A serious fault condition occurred in the game. The game will shut down.\n");
+		fmt::print("As you loaded an emergency savegame no crash information will be generated.\n");
 		abort();
 	}
 
 	if (SaveloadCrashWithMissingNewGRFs()) {
-		printf("A serious fault condition occurred in the game. The game will shut down.\n");
-		printf("As you loaded an savegame for which you do not have the required NewGRFs\n");
-		printf("no crash information will be generated.\n");
+		fmt::print("A serious fault condition occurred in the game. The game will shut down.\n");
+		fmt::print("As you loaded an savegame for which you do not have the required NewGRFs\n");
+		fmt::print("no crash information will be generated.\n");
 		abort();
 	}
 
diff --git a/src/pathfinder/npf/aystar.cpp b/src/pathfinder/npf/aystar.cpp
index 163d7859ec..698b8183ac 100644
--- a/src/pathfinder/npf/aystar.cpp
+++ b/src/pathfinder/npf/aystar.cpp
@@ -211,7 +211,7 @@ void AyStar::Free()
 	this->openlist_hash.Delete(true);
 	this->closedlist_hash.Delete(true);
 #ifdef AYSTAR_DEBUG
-	printf("[AyStar] Memory free'd\n");
+	Debug(misc, 0, "[AyStar] Memory free'd");
 #endif
 }
 
@@ -229,7 +229,7 @@ void AyStar::Clear()
 	this->closedlist_hash.Clear(true);
 
 #ifdef AYSTAR_DEBUG
-	printf("[AyStar] Cleared AyStar\n");
+	Debug(misc, 0, "[AyStar] Cleared AyStar");
 #endif
 }
 
@@ -250,9 +250,9 @@ int AyStar::Main()
 	while ((r = this->Loop()) == AYSTAR_STILL_BUSY && (this->loops_per_tick == 0 || ++i < this->loops_per_tick)) { }
 #ifdef AYSTAR_DEBUG
 	switch (r) {
-		case AYSTAR_FOUND_END_NODE: printf("[AyStar] Found path!\n"); break;
-		case AYSTAR_EMPTY_OPENLIST: printf("[AyStar] OpenList run dry, no path found\n"); break;
-		case AYSTAR_LIMIT_REACHED:  printf("[AyStar] Exceeded search_nodes, no path found\n"); break;
+		case AYSTAR_FOUND_END_NODE: Debug(misc, 0, "[AyStar] Found path!"); break;
+		case AYSTAR_EMPTY_OPENLIST: Debug(misc, 0, "[AyStar] OpenList run dry, no path found"); break;
+		case AYSTAR_LIMIT_REACHED:  Debug(misc, 0, "[AyStar] Exceeded search_nodes, no path found"); break;
 		default: break;
 	}
 #endif
@@ -280,7 +280,7 @@ int AyStar::Main()
 void AyStar::AddStartNode(AyStarNode *start_node, uint g)
 {
 #ifdef AYSTAR_DEBUG
-	printf("[AyStar] Starting A* Algorithm from node (%d, %d, %d)\n",
+	Debug(misc, 0, "[AyStar] Starting A* Algorithm from node ({}, {}, {})\n",
 		TileX(start_node->tile), TileY(start_node->tile), start_node->direction);
 #endif
 	this->OpenListAdd(nullptr, start_node, 0, g);
diff --git a/src/pathfinder/npf/queue.cpp b/src/pathfinder/npf/queue.cpp
index 960cda8e5c..f1acf26eb3 100644
--- a/src/pathfinder/npf/queue.cpp
+++ b/src/pathfinder/npf/queue.cpp
@@ -303,29 +303,26 @@ void Hash::PrintStatistics() const
 			max_usage = usage[collision];
 		}
 	}
-	printf(
-		"---\n"
-		"Hash size: %u\n"
-		"Nodes used: %u\n"
-		"Non empty buckets: %u\n"
-		"Max collision: %u\n",
+	Debug(misc, 0, "Hash size: {}, Nodes used: {}, Non empty buckets: {}, Max collision: {}",
 		this->num_buckets, this->size, used_buckets, max_collision
 	);
-	printf("{ ");
+	std::string line;
+	line += "{ ";
 	for (i = 0; i <= max_collision; i++) {
 		if (usage[i] > 0) {
-			printf("%u:%u ", i, usage[i]);
+			fmt::format_to(std::back_inserter(line), "{}:{} ", i, usage[i]);
 #if 0
 			if (i > 0) {
 				uint j;
 
-				for (j = 0; j < usage[i] * 160 / 800; j++) putchar('#');
+				for (j = 0; j < usage[i] * 160 / 800; j++) line += "#";
 			}
-			printf("\n");
+			line += "\n";
 #endif
 		}
 	}
-	printf ("}\n");
+	line += "}";
+	Debug(misc, 0, "{}", line);
 }
 #endif
 
diff --git a/src/script/squirrel.cpp b/src/script/squirrel.cpp
index a59b7cff64..530e0c32d9 100644
--- a/src/script/squirrel.cpp
+++ b/src/script/squirrel.cpp
@@ -269,7 +269,7 @@ void Squirrel::PrintFunc(HSQUIRRELVM vm, const std::string &s)
 	/* Check if we have a custom print function */
 	SQPrintFunc *func = ((Squirrel *)sq_getforeignptr(vm))->print_func;
 	if (func == nullptr) {
-		printf("%s", s.c_str());
+		fmt::print("%s", s);
 	} else {
 		(*func)(false, s);
 	}
diff --git a/src/strgen/strgen.cpp b/src/strgen/strgen.cpp
index e4f4f55ed7..fc58f8a142 100644
--- a/src/strgen/strgen.cpp
+++ b/src/strgen/strgen.cpp
@@ -427,7 +427,7 @@ int CDECL main(int argc, char *argv[])
 				return 0;
 
 			case 'C':
-				printf("args\tflags\tcommand\treplacement\n");
+				fmt::print("args\tflags\tcommand\treplacement\n");
 				for (const CmdStruct *cs = _cmd_structs; cs < endof(_cmd_structs); cs++) {
 					char flags;
 					if (cs->proc == EmitGender) {
@@ -439,21 +439,21 @@ int CDECL main(int argc, char *argv[])
 					} else {
 						flags = '0'; // Command needs no parameters
 					}
-					printf("%i\t%c\t\"%s\"\t\"%s\"\n", cs->consumes, flags, cs->cmd, strstr(cs->cmd, "STRING") ? "STRING" : cs->cmd);
+					fmt::print("{}\t{:c}\t\"{}\"\t\"{}\"\n", cs->consumes, flags, cs->cmd, strstr(cs->cmd, "STRING") ? "STRING" : cs->cmd);
 				}
 				return 0;
 
 			case 'L':
-				printf("count\tdescription\tnames\n");
+				fmt::print("count\tdescription\tnames\n");
 				for (const PluralForm *pf = _plural_forms; pf < endof(_plural_forms); pf++) {
-					printf("%i\t\"%s\"\t%s\n", pf->plural_count, pf->description, pf->names);
+					fmt::print("{}\t\"{}\"\t{}\n", pf->plural_count, pf->description, pf->names);
 				}
 				return 0;
 
 			case 'P':
-				printf("name\tflags\tdefault\tdescription\n");
+				fmt::print("name\tflags\tdefault\tdescription\n");
 				for (size_t j = 0; j < lengthof(_pragmas); j++) {
-					printf("\"%s\"\t%s\t\"%s\"\t\"%s\"\n",
+					fmt::print("\"{}\"\t{}\t\"{}\"\t\"{}\"\n",
 							_pragmas[j][0], _pragmas[j][1], _pragmas[j][2], _pragmas[j][3]);
 				}
 				return 0;