diff --git a/R-package/R/lgb.Dataset.R b/R-package/R/lgb.Dataset.R
index 429eb1f91275..53724a7144a2 100644
--- a/R-package/R/lgb.Dataset.R
+++ b/R-package/R/lgb.Dataset.R
@@ -226,9 +226,18 @@ Dataset <- R6::R6Class(
         ref_handle <- private$reference$.__enclos_env__$private$get_handle()
       }
 
-      # Not subsetting
+      # not subsetting, constructing from raw data
       if (is.null(private$used_indices)) {
 
+        if (is.null(private$raw_data)) {
+          stop(paste0(
+            "Attempting to create a Dataset without any raw data. "
+            , "This can happen if you have called Dataset$finalize() or if this Dataset was saved with saveRDS(). "
+            , "To avoid this error in the future, use lgb.Dataset.save() or "
+            , "Dataset$save_binary() to save lightgbm Datasets."
+          ))
+        }
+
         # Are we using a data file?
         if (is.character(private$raw_data)) {
 
diff --git a/R-package/src/lightgbm_R.cpp b/R-package/src/lightgbm_R.cpp
index b393011186f1..99dd666dbf9e 100644
--- a/R-package/src/lightgbm_R.cpp
+++ b/R-package/src/lightgbm_R.cpp
@@ -90,6 +90,24 @@ void _DatasetFinalizer(SEXP handle) {
   LGBM_DatasetFree_R(handle);
 }
 
+void _AssertBoosterHandleNotNull(SEXP handle) {
+  if (Rf_isNull(handle) || !R_ExternalPtrAddr(handle)) {
+    Rf_error(
+      "Attempting to use a Booster which no longer exists. "
+      "This can happen if you have called Booster$finalize() or if this Booster was saved with saveRDS(). "
+      "To avoid this error in the future, use saveRDS.lgb.Booster() or Booster$save_model() to save lightgbm Boosters.");
+  }
+}
+
+void _AssertDatasetHandleNotNull(SEXP handle) {
+  if (Rf_isNull(handle) || !R_ExternalPtrAddr(handle)) {
+    Rf_error(
+      "Attempting to use a Dataset which no longer exists. "
+      "This can happen if you have called Dataset$finalize() or if this Dataset was saved with saveRDS(). "
+      "To avoid this error in the future, use lgb.Dataset.save() or Dataset$save_binary() to save lightgbm Datasets.");
+  }
+}
+
 SEXP LGBM_DatasetCreateFromFile_R(SEXP filename,
   SEXP parameters,
   SEXP reference) {
@@ -172,6 +190,7 @@ SEXP LGBM_DatasetGetSubset_R(SEXP handle,
   SEXP len_used_row_indices,
   SEXP parameters) {
   R_API_BEGIN();
+  _AssertDatasetHandleNotNull(handle);
   SEXP ret = PROTECT(R_MakeExternalPtr(nullptr, R_NilValue, R_NilValue));
   int32_t len = static_cast<int32_t>(Rf_asInteger(len_used_row_indices));
   std::vector<int32_t> idxvec(len);
@@ -195,6 +214,7 @@ SEXP LGBM_DatasetGetSubset_R(SEXP handle,
 SEXP LGBM_DatasetSetFeatureNames_R(SEXP handle,
   SEXP feature_names) {
   R_API_BEGIN();
+  _AssertDatasetHandleNotNull(handle);
   auto vec_names = Split(CHAR(PROTECT(Rf_asChar(feature_names))), '\t');
   std::vector<const char*> vec_sptr;
   int len = static_cast<int>(vec_names.size());
@@ -211,6 +231,7 @@ SEXP LGBM_DatasetSetFeatureNames_R(SEXP handle,
 SEXP LGBM_DatasetGetFeatureNames_R(SEXP handle) {
   SEXP cont_token = PROTECT(R_MakeUnwindCont());
   R_API_BEGIN();
+  _AssertDatasetHandleNotNull(handle);
   SEXP feature_names;
   int len = 0;
   CHECK_CALL(LGBM_DatasetGetNumFeature(R_ExternalPtrAddr(handle), &len));
@@ -258,6 +279,7 @@ SEXP LGBM_DatasetGetFeatureNames_R(SEXP handle) {
 SEXP LGBM_DatasetSaveBinary_R(SEXP handle,
   SEXP filename) {
   R_API_BEGIN();
+  _AssertDatasetHandleNotNull(handle);
   const char* filename_ptr = CHAR(PROTECT(Rf_asChar(filename)));
   CHECK_CALL(LGBM_DatasetSaveBinary(R_ExternalPtrAddr(handle),
     filename_ptr));
@@ -281,6 +303,7 @@ SEXP LGBM_DatasetSetField_R(SEXP handle,
   SEXP field_data,
   SEXP num_element) {
   R_API_BEGIN();
+  _AssertDatasetHandleNotNull(handle);
   int len = Rf_asInteger(num_element);
   const char* name = CHAR(PROTECT(Rf_asChar(field_name)));
   if (!strcmp("group", name) || !strcmp("query", name)) {
@@ -309,6 +332,7 @@ SEXP LGBM_DatasetGetField_R(SEXP handle,
   SEXP field_name,
   SEXP field_data) {
   R_API_BEGIN();
+  _AssertDatasetHandleNotNull(handle);
   const char* name = CHAR(PROTECT(Rf_asChar(field_name)));
   int out_len = 0;
   int out_type = 0;
@@ -343,6 +367,7 @@ SEXP LGBM_DatasetGetFieldSize_R(SEXP handle,
   SEXP field_name,
   SEXP out) {
   R_API_BEGIN();
+  _AssertDatasetHandleNotNull(handle);
   const char* name = CHAR(PROTECT(Rf_asChar(field_name)));
   int out_len = 0;
   int out_type = 0;
@@ -370,6 +395,7 @@ SEXP LGBM_DatasetUpdateParamChecking_R(SEXP old_params,
 
 SEXP LGBM_DatasetGetNumData_R(SEXP handle, SEXP out) {
   R_API_BEGIN();
+  _AssertDatasetHandleNotNull(handle);
   int nrow;
   CHECK_CALL(LGBM_DatasetGetNumData(R_ExternalPtrAddr(handle), &nrow));
   INTEGER(out)[0] = nrow;
@@ -380,6 +406,7 @@ SEXP LGBM_DatasetGetNumData_R(SEXP handle, SEXP out) {
 SEXP LGBM_DatasetGetNumFeature_R(SEXP handle,
   SEXP out) {
   R_API_BEGIN();
+  _AssertDatasetHandleNotNull(handle);
   int nfeature;
   CHECK_CALL(LGBM_DatasetGetNumFeature(R_ExternalPtrAddr(handle), &nfeature));
   INTEGER(out)[0] = nfeature;
@@ -406,6 +433,7 @@ SEXP LGBM_BoosterFree_R(SEXP handle) {
 SEXP LGBM_BoosterCreate_R(SEXP train_data,
   SEXP parameters) {
   R_API_BEGIN();
+  _AssertDatasetHandleNotNull(train_data);
   SEXP ret = PROTECT(R_MakeExternalPtr(nullptr, R_NilValue, R_NilValue));
   const char* parameters_ptr = CHAR(PROTECT(Rf_asChar(parameters)));
   BoosterHandle handle = nullptr;
@@ -448,6 +476,8 @@ SEXP LGBM_BoosterLoadModelFromString_R(SEXP model_str) {
 SEXP LGBM_BoosterMerge_R(SEXP handle,
   SEXP other_handle) {
   R_API_BEGIN();
+  _AssertBoosterHandleNotNull(handle);
+  _AssertBoosterHandleNotNull(other_handle);
   CHECK_CALL(LGBM_BoosterMerge(R_ExternalPtrAddr(handle), R_ExternalPtrAddr(other_handle)));
   return R_NilValue;
   R_API_END();
@@ -456,6 +486,8 @@ SEXP LGBM_BoosterMerge_R(SEXP handle,
 SEXP LGBM_BoosterAddValidData_R(SEXP handle,
   SEXP valid_data) {
   R_API_BEGIN();
+  _AssertBoosterHandleNotNull(handle);
+  _AssertDatasetHandleNotNull(valid_data);
   CHECK_CALL(LGBM_BoosterAddValidData(R_ExternalPtrAddr(handle), R_ExternalPtrAddr(valid_data)));
   return R_NilValue;
   R_API_END();
@@ -464,6 +496,8 @@ SEXP LGBM_BoosterAddValidData_R(SEXP handle,
 SEXP LGBM_BoosterResetTrainingData_R(SEXP handle,
   SEXP train_data) {
   R_API_BEGIN();
+  _AssertBoosterHandleNotNull(handle);
+  _AssertDatasetHandleNotNull(train_data);
   CHECK_CALL(LGBM_BoosterResetTrainingData(R_ExternalPtrAddr(handle), R_ExternalPtrAddr(train_data)));
   return R_NilValue;
   R_API_END();
@@ -472,6 +506,7 @@ SEXP LGBM_BoosterResetTrainingData_R(SEXP handle,
 SEXP LGBM_BoosterResetParameter_R(SEXP handle,
   SEXP parameters) {
   R_API_BEGIN();
+  _AssertBoosterHandleNotNull(handle);
   const char* parameters_ptr = CHAR(PROTECT(Rf_asChar(parameters)));
   CHECK_CALL(LGBM_BoosterResetParameter(R_ExternalPtrAddr(handle), parameters_ptr));
   UNPROTECT(1);
@@ -482,6 +517,7 @@ SEXP LGBM_BoosterResetParameter_R(SEXP handle,
 SEXP LGBM_BoosterGetNumClasses_R(SEXP handle,
   SEXP out) {
   R_API_BEGIN();
+  _AssertBoosterHandleNotNull(handle);
   int num_class;
   CHECK_CALL(LGBM_BoosterGetNumClasses(R_ExternalPtrAddr(handle), &num_class));
   INTEGER(out)[0] = num_class;
@@ -491,6 +527,7 @@ SEXP LGBM_BoosterGetNumClasses_R(SEXP handle,
 
 SEXP LGBM_BoosterUpdateOneIter_R(SEXP handle) {
   R_API_BEGIN();
+  _AssertBoosterHandleNotNull(handle);
   int is_finished = 0;
   CHECK_CALL(LGBM_BoosterUpdateOneIter(R_ExternalPtrAddr(handle), &is_finished));
   return R_NilValue;
@@ -502,6 +539,7 @@ SEXP LGBM_BoosterUpdateOneIterCustom_R(SEXP handle,
   SEXP hess,
   SEXP len) {
   R_API_BEGIN();
+  _AssertBoosterHandleNotNull(handle);
   int is_finished = 0;
   int int_len = Rf_asInteger(len);
   std::vector<float> tgrad(int_len), thess(int_len);
@@ -517,6 +555,7 @@ SEXP LGBM_BoosterUpdateOneIterCustom_R(SEXP handle,
 
 SEXP LGBM_BoosterRollbackOneIter_R(SEXP handle) {
   R_API_BEGIN();
+  _AssertBoosterHandleNotNull(handle);
   CHECK_CALL(LGBM_BoosterRollbackOneIter(R_ExternalPtrAddr(handle)));
   return R_NilValue;
   R_API_END();
@@ -525,6 +564,7 @@ SEXP LGBM_BoosterRollbackOneIter_R(SEXP handle) {
 SEXP LGBM_BoosterGetCurrentIteration_R(SEXP handle,
   SEXP out) {
   R_API_BEGIN();
+  _AssertBoosterHandleNotNull(handle);
   int out_iteration;
   CHECK_CALL(LGBM_BoosterGetCurrentIteration(R_ExternalPtrAddr(handle), &out_iteration));
   INTEGER(out)[0] = out_iteration;
@@ -535,6 +575,7 @@ SEXP LGBM_BoosterGetCurrentIteration_R(SEXP handle,
 SEXP LGBM_BoosterGetUpperBoundValue_R(SEXP handle,
   SEXP out_result) {
   R_API_BEGIN();
+  _AssertBoosterHandleNotNull(handle);
   double* ptr_ret = REAL(out_result);
   CHECK_CALL(LGBM_BoosterGetUpperBoundValue(R_ExternalPtrAddr(handle), ptr_ret));
   return R_NilValue;
@@ -544,6 +585,7 @@ SEXP LGBM_BoosterGetUpperBoundValue_R(SEXP handle,
 SEXP LGBM_BoosterGetLowerBoundValue_R(SEXP handle,
   SEXP out_result) {
   R_API_BEGIN();
+  _AssertBoosterHandleNotNull(handle);
   double* ptr_ret = REAL(out_result);
   CHECK_CALL(LGBM_BoosterGetLowerBoundValue(R_ExternalPtrAddr(handle), ptr_ret));
   return R_NilValue;
@@ -553,6 +595,7 @@ SEXP LGBM_BoosterGetLowerBoundValue_R(SEXP handle,
 SEXP LGBM_BoosterGetEvalNames_R(SEXP handle) {
   SEXP cont_token = PROTECT(R_MakeUnwindCont());
   R_API_BEGIN();
+  _AssertBoosterHandleNotNull(handle);
   SEXP eval_names;
   int len;
   CHECK_CALL(LGBM_BoosterGetEvalCounts(R_ExternalPtrAddr(handle), &len));
@@ -602,6 +645,7 @@ SEXP LGBM_BoosterGetEval_R(SEXP handle,
   SEXP data_idx,
   SEXP out_result) {
   R_API_BEGIN();
+  _AssertBoosterHandleNotNull(handle);
   int len;
   CHECK_CALL(LGBM_BoosterGetEvalCounts(R_ExternalPtrAddr(handle), &len));
   double* ptr_ret = REAL(out_result);
@@ -616,6 +660,7 @@ SEXP LGBM_BoosterGetNumPredict_R(SEXP handle,
   SEXP data_idx,
   SEXP out) {
   R_API_BEGIN();
+  _AssertBoosterHandleNotNull(handle);
   int64_t len;
   CHECK_CALL(LGBM_BoosterGetNumPredict(R_ExternalPtrAddr(handle), Rf_asInteger(data_idx), &len));
   INTEGER(out)[0] = static_cast<int>(len);
@@ -627,6 +672,7 @@ SEXP LGBM_BoosterGetPredict_R(SEXP handle,
   SEXP data_idx,
   SEXP out_result) {
   R_API_BEGIN();
+  _AssertBoosterHandleNotNull(handle);
   double* ptr_ret = REAL(out_result);
   int64_t out_len;
   CHECK_CALL(LGBM_BoosterGetPredict(R_ExternalPtrAddr(handle), Rf_asInteger(data_idx), &out_len, ptr_ret));
@@ -659,6 +705,7 @@ SEXP LGBM_BoosterPredictForFile_R(SEXP handle,
   SEXP parameter,
   SEXP result_filename) {
   R_API_BEGIN();
+  _AssertBoosterHandleNotNull(handle);
   const char* data_filename_ptr = CHAR(PROTECT(Rf_asChar(data_filename)));
   const char* parameter_ptr = CHAR(PROTECT(Rf_asChar(parameter)));
   const char* result_filename_ptr = CHAR(PROTECT(Rf_asChar(result_filename)));
@@ -680,6 +727,7 @@ SEXP LGBM_BoosterCalcNumPredict_R(SEXP handle,
   SEXP num_iteration,
   SEXP out_len) {
   R_API_BEGIN();
+  _AssertBoosterHandleNotNull(handle);
   int pred_type = GetPredictType(is_rawscore, is_leafidx, is_predcontrib);
   int64_t len = 0;
   CHECK_CALL(LGBM_BoosterCalcNumPredict(R_ExternalPtrAddr(handle), Rf_asInteger(num_row),
@@ -704,6 +752,7 @@ SEXP LGBM_BoosterPredictForCSC_R(SEXP handle,
   SEXP parameter,
   SEXP out_result) {
   R_API_BEGIN();
+  _AssertBoosterHandleNotNull(handle);
   int pred_type = GetPredictType(is_rawscore, is_leafidx, is_predcontrib);
   const int* p_indptr = INTEGER(indptr);
   const int32_t* p_indices = reinterpret_cast<const int32_t*>(INTEGER(indices));
@@ -735,6 +784,7 @@ SEXP LGBM_BoosterPredictForMat_R(SEXP handle,
   SEXP parameter,
   SEXP out_result) {
   R_API_BEGIN();
+  _AssertBoosterHandleNotNull(handle);
   int pred_type = GetPredictType(is_rawscore, is_leafidx, is_predcontrib);
   int32_t nrow = static_cast<int32_t>(Rf_asInteger(num_row));
   int32_t ncol = static_cast<int32_t>(Rf_asInteger(num_col));
@@ -755,6 +805,7 @@ SEXP LGBM_BoosterSaveModel_R(SEXP handle,
   SEXP feature_importance_type,
   SEXP filename) {
   R_API_BEGIN();
+  _AssertBoosterHandleNotNull(handle);
   const char* filename_ptr = CHAR(PROTECT(Rf_asChar(filename)));
   CHECK_CALL(LGBM_BoosterSaveModel(R_ExternalPtrAddr(handle), 0, Rf_asInteger(num_iteration), Rf_asInteger(feature_importance_type), filename_ptr));
   UNPROTECT(1);
@@ -767,6 +818,7 @@ SEXP LGBM_BoosterSaveModelToString_R(SEXP handle,
   SEXP feature_importance_type) {
   SEXP cont_token = PROTECT(R_MakeUnwindCont());
   R_API_BEGIN();
+  _AssertBoosterHandleNotNull(handle);
   SEXP model_str;
   int64_t out_len = 0;
   int64_t buf_len = 1024 * 1024;
@@ -791,6 +843,7 @@ SEXP LGBM_BoosterDumpModel_R(SEXP handle,
   SEXP feature_importance_type) {
   SEXP cont_token = PROTECT(R_MakeUnwindCont());
   R_API_BEGIN();
+  _AssertBoosterHandleNotNull(handle);
   SEXP model_str;
   int64_t out_len = 0;
   int64_t buf_len = 1024 * 1024;
diff --git a/R-package/tests/testthat/test_dataset.R b/R-package/tests/testthat/test_dataset.R
index 04ca2e3d1cd3..d8eb0b06ce1e 100644
--- a/R-package/tests/testthat/test_dataset.R
+++ b/R-package/tests/testthat/test_dataset.R
@@ -496,3 +496,51 @@ test_that("lgb.Dataset: should be able to create a Dataset from a text file with
   expect_identical(dtrain$get_params(), list(header = FALSE))
   expect_identical(dtrain$dim(), c(100L, 2L))
 })
+
+test_that("Dataset: method calls on a Dataset with a null handle should raise an informative error and not segfault", {
+  data(agaricus.train, package = "lightgbm")
+  train <- agaricus.train
+  dtrain <- lgb.Dataset(train$data, label = train$label)
+  dtrain$construct()
+  dvalid <- dtrain$create_valid(
+    data = train$data[seq_len(100L), ]
+    , label = train$label[seq_len(100L)]
+  )
+  dvalid$construct()
+  tmp_file <- tempfile(fileext = ".rds")
+  saveRDS(dtrain, tmp_file)
+  rm(dtrain)
+  dtrain <- readRDS(tmp_file)
+  expect_error({
+    dtrain$construct()
+  }, regexp = "Attempting to create a Dataset without any raw data")
+  expect_error({
+    dtrain$dim()
+  }, regexp = "cannot get dimensions before dataset has been constructed")
+  expect_error({
+    dtrain$get_colnames()
+  }, regexp = "cannot get column names before dataset has been constructed")
+  expect_error({
+    dtrain$save_binary(fname = tempfile(fileext = ".bin"))
+  }, regexp = "Attempting to create a Dataset without any raw data")
+  expect_error({
+    dtrain$set_categorical_feature(categorical_feature = 1L)
+  }, regexp = "cannot set categorical feature after freeing raw data")
+  expect_error({
+    dtrain$set_reference(reference = dvalid)
+  }, regexp = "cannot set reference after freeing raw data")
+
+  tmp_valid_file <- tempfile(fileext = ".rds")
+  saveRDS(dvalid, tmp_valid_file)
+  rm(dvalid)
+  dvalid <- readRDS(tmp_valid_file)
+  dtrain <- lgb.Dataset(
+    train$data
+    , label = train$label
+    , free_raw_data = FALSE
+  )
+  dtrain$construct()
+  expect_error({
+    dtrain$set_reference(reference = dvalid)
+  }, regexp = "cannot get column names before dataset has been constructed")
+})
diff --git a/R-package/tests/testthat/test_lgb.Booster.R b/R-package/tests/testthat/test_lgb.Booster.R
index 7ec7ff86285b..af1ecb3c7504 100644
--- a/R-package/tests/testthat/test_lgb.Booster.R
+++ b/R-package/tests/testthat/test_lgb.Booster.R
@@ -819,6 +819,93 @@ test_that("early_stopping, num_iterations are stored correctly in model string e
 
 })
 
+test_that("Booster: method calls Booster with a null handle should raise an informative error and not segfault", {
+    data(agaricus.train, package = "lightgbm")
+    train <- agaricus.train
+    dtrain <- lgb.Dataset(train$data, label = train$label)
+    bst <- lgb.train(
+        params = list(
+            objective = "regression"
+            , metric = "l2"
+            , num_leaves = 8L
+        )
+        , data = dtrain
+        , verbose = -1L
+        , nrounds = 5L
+        , valids = list(
+            train = dtrain
+        )
+    )
+    tmp_file <- tempfile(fileext = ".rds")
+    saveRDS(bst, tmp_file)
+    rm(bst)
+    bst <- readRDS(tmp_file)
+    .expect_booster_error <- function(object) {
+        error_regexp <- "Attempting to use a Booster which no longer exists"
+        expect_error(object, regexp = error_regexp)
+    }
+    .expect_booster_error({
+        bst$current_iter()
+    })
+    .expect_booster_error({
+        bst$dump_model()
+    })
+    .expect_booster_error({
+        bst$eval(data = dtrain, name = "valid")
+    })
+    .expect_booster_error({
+        bst$eval_train()
+    })
+    .expect_booster_error({
+        bst$lower_bound()
+    })
+    .expect_booster_error({
+        bst$predict(data = train$data[seq_len(5L), ])
+    })
+    .expect_booster_error({
+        bst$reset_parameter(params = list(learning_rate = 0.123))
+    })
+    .expect_booster_error({
+        bst$rollback_one_iter()
+    })
+    .expect_booster_error({
+        bst$save()
+    })
+    .expect_booster_error({
+        bst$save_model(filename = tempfile(fileext = ".model"))
+    })
+    .expect_booster_error({
+        bst$save_model_to_string()
+    })
+    .expect_booster_error({
+        bst$update()
+    })
+    .expect_booster_error({
+        bst$upper_bound()
+    })
+    predictor <- bst$to_predictor()
+    .expect_booster_error({
+        predictor$current_iter()
+    })
+    .expect_booster_error({
+        predictor$predict(data = train$data[seq_len(5L), ])
+    })
+})
+
+test_that("Booster$new() using a Dataset with a null handle should raise an informative error and not segfault", {
+    data(agaricus.train, package = "lightgbm")
+    train <- agaricus.train
+    dtrain <- lgb.Dataset(train$data, label = train$label)
+    dtrain$construct()
+    tmp_file <- tempfile(fileext = ".bin")
+    saveRDS(dtrain, tmp_file)
+    rm(dtrain)
+    dtrain <- readRDS(tmp_file)
+    expect_error({
+        bst <- Booster$new(train_set = dtrain)
+    }, regexp = "lgb.Booster: cannot create Booster handle")
+})
+
 # this is almost identical to the test above it, but for lgb.cv(). A lot of code
 # is duplicated between lgb.train() and lgb.cv(), and this will catch cases where
 # one is updated and the other isn't